English

• 1.   Introduction

  Recently, multi-component reactions (MCRs) have attracted much interest and have emerged as valuable tools for the synthesis of functionalized organic compounds via C—C and C—hetero atom bonds conformations in one-pot.^[1] MCRs is an innovative strategy to create combinatorial libraries of disparate organic compounds which are important for pharmacology, and it has served effective scaffolds for novel drug research. Besides, the ascendancies of MCRs are satisfactory atom-economy, high selectivity and simple procedures. Therefore, the investigation of novel MCRs is a widespread hot spot in modern chemistry and is excellent in green chemistry.

  Xanthenes and benzoxanthenones have been receiving considerable attention due to the special biological characters, like antiviral, ^[2] anti-bacterial^[3] and anti-inflammatory attributes.^[4] Besides, such heterocyclic compounds have frequently served as dyes, ^[5] pH-sensitive fluorescent substances^[6] and key laser material.^[7] So, the creative preparation for xanthene derivatives is of significance. Various strategies have emerged for the xanthene derivatives preparation in literature.^[8] Currently, the mostly used method toward 12-aryl-8, 9, 10, 12-tetrahydrobenzo[a]-xanthen-11- ones, one of the most important xanthene derivatives, is the one-pot MCR from β-naphthol, arylaldehydes and 1, 3-dicarbonyl compounds. This MCR can be accelerated by acid or other type of catalysts, such as p-TSA, ^[9] acidic ionic liquid, ^[10] NH₂SO₃H, ^[11] I₂, ^[12] Sr(OTf)₂, ^[13] InCl₃ or P₂O₅, ^[14] glucose sulfonic acid, ^[15] TPPMS/CBr₄, ^[16] TrCl, ^[17] KAl(SO₄)₂•12H₂O, ^[18] Ce-MCM-41, ^[19] HY zeolite, ^[20] BNPs-TAPC, ^[21] Fe₃O₄/CS NPs, ^[22] BTMA-Br₃, ^[23] and sulfated polyborate.^[24] Xanthenediones also can be prepared by microwave^[25] or ultrasound conditions.^[26] Despite the effectiveness, some drawbacks still exist in these methods, for instance, expensive catalysts, low yields, longer reaction time, adopting poisonous organic reagents and rigorous reaction conditions. Hence, the investigation of novel catalysts toward the preparation of various xanthene derivatives is in great demand.

  Ionic liquid (IL), a typical kind of molten salts with low vapor pressure, is becoming more and more popular in chemistry, pharmacy, nanoscience and energy storage.^[27] Specially, IL as a novel catalyst and neoteric media has experienced a rapid development in the past few years, and a variety of new reactions have been successfully developed in IL.^[28] Nowadays, greater enthusiasm has been put on IL in catalytic science, not only for the growing awareness of developing greener reactions or process, but also due to the consideration of high efficiency and precise preparation in chemistry. Recently, supported IL (SIL) experienced fast development by immobilization of IL using various inorganic and polymeric supports, aiming to improve their adaptability in industrially significant catalytic processes.^[29]

  Among various supports for IL immobilization, β-cyclodextrin (β-CD) is of interest for its unique structure and properties.^[30] β-CD is made up of seven α-(1, 4)-lin- kaged D-glucopyranose monomers. The hydrophilic exterior and lipophilic cavity of β-CD make it suitable for the wrapping of suitably sized guest molecules.^[31] This excellent characteristic has long been exploited in pharmacy, cosmetic, food and chemical industries.^[32] Pristine β-CD and CDs modified with functional groups have been exhumed as catalyst in chemical reactions.^[33] Moreover, β-CD has emerged as possible environmentally friendly supports for catalysts to improve the selectivity of chemical reactions. These features prompted us to exploit new functionalized CDs as catalysts.

  In order to develop new β-CDs based catalytic systems, ^[34] a hybrid system constituted by β-CDs and acid IL (β-CD-AIL) was designed. The catalytic properties of β-CD-AIL was examined for one-pot MCR of β-naphthol, aromatic aldehydes and cyclic 1, 3-dicarbonyl compounds under mild reaction situations (Scheme 1). As known to all, this reaction catalyzed by β-CD-AIL is not yet reported. This catalytic system not only makes the reaction procedure neat, simple and low cost, but also corresponds to the formation of the target products in satisfied yields.

  Scheme 1

  

  Scheme 1.  Preparation of tetrahydrobenzo[a]xanthen-11-ones

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  2.   Results and discussion

  β-CD-AIL was synthesized following the synthetic route (Scheme 2). Firstly, β-CD was treated successively with TsCl to obtain 6-monotosyl-β-CD, which further reacted with diethylamine to afford β-CD-DEA. Subsequently, β- CD-DEA was subjected to addition of 1 and 3-propane sultone, and then further dealed with H₂SO₄ to obtain β-CD-AIL.

  Scheme 2

  

  Scheme 2.  Synthesis of β-CD-AIL

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  β-CD-AIL was confirmed by FT-IR and NMR. The FT-IR spectrum of β-CD shows characteristic absorption bands for O—H stretching vibration, C—H stretching vibration and C—OH stretching vibration at 3396, 2926, 1028 cm^－1, respectively. Correspondingly, the absorption peaks positioned at around 3392, 2927, 1647, 1418 and 1153 cm^－1 are assigned to the bonds in β-CD- AIL frames based on the structure of β-CD. It indicated that β-CD-AIL is made up chiefly by β-CD frameworks. The adsorption peaks at 1460 and 1370 cm^－1 attributed for CH₃ stretching. Two characteristic adsorption bands at 1206 and 1032 cm^－1 corresponding to the S＝O stretching vibration of propyl sulfonic acid were observed, illustrating the formation of desired β-CD-AIL.

  ¹H NMR spectra of β-CD, β-CD-DEA and β-CD- AIL are shown in Figure 2. The characteristic methyl peaks of β-CD-DEA (δ 0.97) and β-CD-AIL (δ 1.07) were observed. Compared to β-CD, the two characteristic peaks situated at δ 1.93 (CH₂CH₂CH₂SO₃H) and 2.88 (CH₂CH₂- CH₂SO₃H) are observed from the spectrum of β-CD-AIL. Owing to N-ethyl and N-propylsulfonic acid modified β-CD, the C₁—H of β-CD-AIL was divided into a pair of peaks at δ 4.94 and 5.10. The significant distinguish for ¹H NMR spectra exactly approved that β-CD was well functionalized by the acid IL via covalent bonds.

  Figure 1

  

  Figure 1.  FT-IR spectra of (i) β-CD and (ii) β-CD-AIL

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  Figure 2

  

  Figure 2.  ¹H NMR spectra of β-CD, β-CD-DEA and β-CD-AIL in D₂O

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  To optimize the best experimental conditions, the one- pot MCR of benzaldehyde (1a), β-naphthol (2) and dimedone (3a) was carried out using various amounts of β-CD-AIL under different reaction parameters. The corresponding results are depicted in Table 1. Without β-CD- AIL as catalyst, no expected product was obtained even after increasing reaction temperature and/or prolonging reaction time (Table 1, Entries 1~2). It revealed that this reaction probably needs a certain kind of catalyst. Interestingly, when the same reaction carried out with β-CD-AIL (3 mol%) in water, the reaction yield increased to 24% (Table 1, Entry 3). When increased reaction temperature to 50, 80 and 100 ℃, the corresponding yields were 81%, 92% and 91%, respectively (Table 1, Entries 4~6). It can be seen that the best yield generated under the temperature of 80 ℃. When 1, 3 and 5 mol% of β-CD-AILs were used at 80 ℃, the corresponding yields were 79%, 92% and 92% (Table 1, Entries 7, 5 and 8). Therefore, 3 mol% β-CD-AIL was enough and increased catalyst quality did not promote the product effectively (Table 1, Entry 8). β-CD, acid IL (N, N, N-triethyl-N-(3-sulfopropyl)ammo- nium hydrogen sulfate) and β-CD/acid IL were examined under the same conditions. However, when compared to β-CD-AIL, they exhibit low activity (Table 1, Entries 15~16). Using various solvents, for example, CH₃CN, ethanol, DMF, ClCH₂CH₂Cl and THF, the yields were not satisfactory, only ranging from 56% to 88% (Table 1, Entries 9~14). The best results were obtained in water. Thus, the optimal reaction parameters were determined as that the catalytic reaction was promoted by β-CD-AIL (3 mol%) in water at 80 ℃.

  Table 1

  

  Table 1.  Optimization of reaction conditions for the synthesis of 4a^a

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  Entry	Solvent	Catalyst	Cat./ mol%	T/℃	Time/ min	Yieldb/%
  1	H2O	—	—	r.t.	120	NRc
  2	H2O	—	—	80	120	NRc
  3	H2O	β-CD-AIL	3	r.t.	120	24
  4	H2O	β-CD-AIL	3	50	60	81
  5	H2O	β-CD-AIL	3	80	30	92
  6	H2O	β-CD-AIL	3	100	30	91
  7	H2O	β-CD-AIL	1	80	30	79
  8	H2O	β-CD-AIL	5	80	30	92
  9	Solvent-free	β-CD-AIL	3	80	30	85
  10	CH3CH2OH	β-CD-AIL	3	80	30	88
  11	ClCH2CH2Cl	β-CD-AIL	3	80	30	72
  12	THF	β-CD-AIL	3	80	30	68
  13	CH3CN	β-CD-AIL	3	80	30	56
  14	DMF	β-CD-AIL	3	80	30	78
  15	H2O	β-CD	3	80	30	10
  16	H2O	AILd	3	80	30	76
  17	H2O	β-CD+AIL	3+3	80	30	81
  a Reaction condition: benzaldehyde (2 mmol), β-naphthol (2 mmol) and dimedone (2 mmol), solvent-free or solvent (3 mL). b Isolated yield. c No reaction was observed. d AIL: N, N, N-triethyl-N-(3-sulfopropyl)ammonium hydrogen sulfate.

  To determine the scope of this protocol, a series of aromatic aldehydes and cyclic 1, 3-dicarbonyl compounds were explored under the optimized parameters. The delighted results are observed, which are summarized in Table 2. The results showed that aromatic aldehydes bearing electron-donating groups (Entries 9~13 and 19~21) demanded prelonged time to accomplish the reaction compared to those including electron-withdrawing groups (Entries 3, 4, 8). Either 1, 3-cyclehexanedione or dimedone showed good production. The results reveal that β-CD-AIL is an effective catalyst for such class of reactions in water.

  Table 2

  

  Table 2.  Synthesis of tetrahydrobenzo[a]xanthen-11-ones catalyzed by β-CD-AIL in water^a

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  Entry	Ar	R1	Compd.	Time/min	Yieldb/%
  1	C6H5	CH3	4a	30	92
  2	2-Cl-C6H4	CH3	4b	30	90
  3	4-Cl-C6H4	CH3	4c	25	94
  4	2, 4-Cl2-C6H4	CH3	4d	30	88
  5	4-F-C6H4	CH3	4e	20	92
  6	2-NO2-C6H4	CH3	4f	25	91
  7	3-NO2-C6H4	CH3	4g	25	90
  8	4-NO2-C6H4	CH3	4h	20	95
  9	4-CH3-C6H4	CH3	4i	30	91
  10	4-CH3O-C6H4	CH3	4j	35	88
  11	2-HO-C6H4	CH3	4k	30	82
  12	4-HO-C6H4	CH3	4l	30	85
  13	4-N(CH3)2-C6H4	CH3	4m	30	90
  14	C6H5	H	4n	30	90
  15	2-Cl-C6H4	H	4o	30	89
  16	4-Cl-C6H4	H	4p	25	92
  17	3-NO2-C6H4	H	4q	25	91
  18	4-NO2-C6H4	H	4r	20	93
  19	4-CH3-C6H4	H	4s	30	90
  20	4-CH3O-C6H4	H	4t	40	86
  21	4-OH-C6H4	H	4u	40	83
  a Reaction condition: aldehyde (2 mmol), β-naphthol (2 mmol), dimedone or 1, 3-cyclohexanedione (2 mmol), β-CD-AIL (0.06 mmol), H2O (3 mL), 80 ℃. b Isolated yield.

  To investigate the reusability of β-CD-AIL, recycling studies were carried out for the preparation of 4a. When the reaction is over, the reaction mixture was diluted with H₂O (5 mL). The expected product was collected by filtration and recrystallization in ethanol for further purification. For the purpose to reuse the catalyst, H₂O was evaporated through vacuum distillation, and the remaining catalyst was reused directly for the next run. Our results revealed that β-CD-AIL could withstand at least six repeatedly utilization with almost none or only a slight loss of catalytic activity (Figure 3).

  Figure 3

  

  Figure 3.  Reusability of β-CD-AIL for the synthesis of 4a

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  Based on the obtained results and reported literature, ^{[22, 23]} a possible mechanism for this MCR is exhibited in Scheme 3. The intermediate Ⅰ is formed via the aldehyde protonating by H⁺ of β-CD-AIL. Subsequently, the nucleophile β-naphthol (2) activating by β-CD-AIL attacked immediately to the intermediate Ⅰ, that leads to the generation of the adduct Ⅱ. Ⅱ gives ortho-quinonemethides (o-QMs, Ⅲ) upon dehydration. Afterwards, the Michael acceptor intermediate Ⅲ, one of β-CD-AIL activates, is subsequently attacked by the nucleophile Ⅳ that has been activated in advance via deprotonation of 1, 3-cyclohexa- nediones by β-CD-AIL. The final result of this MCR is the generation of Ⅴ which cyclizes to Ⅵ and afterward affords the desired product 4 upon evaporation.

  Scheme 3

  

  Scheme 3.  Plausible mechanism for the β-CD-AIL catalyzed this MCR in water

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  3.   Conclusions

  In summary, we have put forward a facile, eco-friendly, efficient strategy for the preparation of 12-aryl-8, 9, 10, 12- tetrahydrobenzo[a]xanthen-11-ones via the one-pot MCR of β-naphthol, aromatic aldehydes and cyclic 1, 3-dicar- bonyl compounds catalyzed by β-CD-AIL in water. The remarkable ascendancies of this strategy include simple work-up, shortened reaction time, improved catalytic activity, nice reusability, outstanding yields and mild reaction conditions. Thence, this strategy is a more powerful and functional alternative for both laboratory and industrial applications in green chemistry.

  4.   Experimental section

  4.1   General methods

  All commercial chemicals and reagents were used without further purification. FT-IR spectra were determined on a Bruker Vecter 22 by the KBr pellet technique in the range of 500~4000 cm^－1. NMR spectra were recorded in D₂O, DMSO-d₆ or CDCl₃ with TMS as internal standard using a Bruker Avance spectrometer (400 MHz). Melting points were recorded on an X6-data microscopic melting point instrument. Elemental analyses were determined on an Elementar Varioel spectrometer. Electrospray ionization mass spectra were recorded on a Thermo Scientific mass spectrometer.

  4.2   Preparation of β-CD-AIL

  Preparation of 6-O-monotosyl-β-CD (β-CD-OTs): In a round-bottom flask, β-CD (11.35 g, 10 mmol) were dissolved in NaOH solution (1 mol•L^－1, 250 mL). The resulting mixture was stirred at 0~5 ℃, and p-toluenesulfonyl chloride (TsCl, 7.628 g, 40 mmol) was added dropwise in 1 h. The reaction mixture was stirred vigorously at 25 ℃ for 4 h. The unreacted TsCl was filtered off, and the filtrate was adjusted to neutral using concentrated HCl. The product was precipitated, filtered, washed and dried in vacuum. The β-CD-OTs was recrystallized from water to get final pure β-CD-OTs 3.03 g, yield 23.5%. White solid, m.p. 171~173 ℃; ¹H NMR (400 MHz, DMSO-d₆) δ: 7.75 (d, J＝8.3 Hz, 2H), 7.43 (d, J＝8.2 Hz, 2H), 5.92~5.60 (m, 14H), 4.88~4.70 (m, 7H), 4.59~4.26 (m, 7H), 3.77~3.42 (m, 28H), 3.34~3.16 (m, 14H), 2.43 (s, 3H); FT-IR (KBr) v: 3395, 2928, 1645, 1410, 1363, 1156, 1078, 1030, 945, 814, 756, 706, 667, 579 cm^－1.

  Preparation of diethylamine modified β-CD (β-CD- DEA): The mixture of β-CD-OTs (2.578 g, 2 mmol) and diethylamine (10 mL) was refluxed for 24 h. The excessive diethylamine was evaporated, and the residue was dissolved in minimum distilled water at 60 ℃. After cooling, the product was precipitated with acetone. The resulting mixture was filtered and the filter cake was washed with acetone. After dried under vacuum, β-CD-DEA was obtained with 1.55 g, yield 65.1%. White solid, m.p. 248~248 ℃; ¹H NMR (400 MHz, D₂O) δ: 5.11~5.01 (m, 7H), 4.08~3.67 (m, 26H), 3.64~3.45 (m, 12H), 3.35~3.31 (m, 1H), 2.91~2.88 (m, 1H), 2.76~2.48 (m, 6H), 0.97 (t, J＝7.1 Hz, 6H); FT-IR (KBr) v: 3383, 2928, 1645, 1412, 1365, 1155, 1078, 1030, 945, 858, 756, 706, 578 cm^－1.

  Preparation of acid IL functionalized β-CD-DEA (β-CD-AIL): In a round-bottom flask, β-CD-DEA (1.190 g, 1 mmol) and 1, 3-propane sultone (0.182, 1.5 mmol) were added in water (10 mL). The reaction solution was stirred at 80 ℃ for 12 h. Subsequent cooling, the resulting mixture was dealt with H₂SO₄ (56 μL, 1 mmol) and stirred at 25 ℃ for another 6 h. The product was precipitated with ethanol. Pure product is obtained via acetone diffusion in DMF as a white solid. Yield: 1.02 g (72.3%). White solid, m.p. 181~183 ℃; ¹H NMR (400 MHz, D₂O) δ: 4.97~4.91 (m, 7H), 4.07~3.65 (m, 28H), 3.63~3.32 (m, 18H), 2.88 (s, 2H), 1.93 (s, 2H), 1.07 (t, J＝7.1 Hz, 6H); FT-IR (KBr) v: 3393, 2928, 1647, 1460, 1418, 1370, 1339, 1153, 1080, 1032, 937, 851, 756, 706, 610, 581 cm^－1; ESI-MS m/z: 1410.42 [M+1]⁺.

  4.3   General procedure for the preparation of tetrahydrobenzo[a]xanthen-11-ones

  In a typical experiment, β-naphthol (2 mmol), aromatic aldehydes (2 mmol), cyclic 1, 3-dicarbonyl compounds (2 mmol) and β-CD-AIL (85 mg) were dissolved in 3 mL of H₂O. The reaction solution was stirred at 80 ℃ for a required period of time (TLC). After reaction completion, the resulting mixture was diluted with H₂O (5 mL). The crude product was filtered. The isolated product was recrystallized from ethanol to obtain the responding product.

  9, 9-Dimethyl-12-phenyl-9, 10-dihydro-8H-benzo[a]xant-hen-11(12H)-one (4a): White solid, m.p. 152~154 ℃ (lit.^[14] 151~152 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.99 (d, J＝8.4 Hz, 1H, ArH), 7.77 (t, J＝7.6 Hz, 2H, ArH), 7.46~7.29 (m, 5H, ArH), 7.17 (t, J＝7.6 Hz, 2H, ArH), 7.05 (t, J＝7.3 Hz, 1H, ArH), 5.70 (s, 1H, CH), 2.57 (s, 2H, CH₂), 2.27 (q, J＝16.3 Hz, 2H, CH₂), 1.11 (s, 3H, CH₃), 0.96 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.93, 163.91, 147.76, 144.76, 131.50, 131.42, 128.84, 128.44, 128.40, 128.25, 127.02, 126.25, 124.91, 123.70, 117.72, 117.06, 114.28, 50.92, 41.43, 34.72, 32.30, 29.32, 27.20; FT-IR (KBr) v: 3438, 2955, 2886, 2361, 1651, 1596, 1375, 1228, 1184, 1029, 811, 746, 699, 658 cm^－1.

  12-(2-Chlorophenyl)-9, 9-dimethyl-9, 10-dihydro-8H-ben-zo[a]xanthen-11(12H)-one (4b): White solid, m.p. 167~169 ℃ (lit.^[22] 166~168 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.12 (d, J＝8.5 Hz, 1H, ArH), 7.77 (t, J＝7.8 Hz, 2H, ArH), 7.50~7.46 (m, 1H, ArH), 7.39 (t, J＝7.1 Hz, 1H, ArH), 7.34~7.26 (m, 3H, ArH), 7.22 (d, J＝8.3 Hz, 1H, ArH), 7.04 (dd, J＝8.4, 2.0 Hz, 1H, ArH), 5.94 (s, 1H, CH), 2.69~2.52 (m, 2H, CH₂), 2.27 (dd, J＝37.3, 16.3 Hz, 2H, CH₂), 1.14 (s, 3H, CH₃), 1.00 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.70, 164.41, 147.72, 133.68, 132.61, 132.52, 131.55, 131.42, 129.67, 129.37, 128.53, 127.28, 127.26, 125.07, 123.68, 117.07, 50.88, 41.49, 32.18, 29.36, 27.16; FT-IR (KBr) v: 2955, 1651, 1597, 1467, 1371, 1222, 1142, 849, 752, 489 cm^－1.

  12-(4-Chlorophenyl)-9, 9-dimethyl-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)-one (4c): White solid, m.p. 181~183 ℃ (lit.^[20] 180~182 ℃); ; ¹H NMR (400 MHz, CDCl₃) δ: 7.90 (d, J＝8.3 Hz, 1H, ArH), 7.82~7.72 (m, 2H, ArH), 7.48~7.35 (m, 2H, ArH), 7.32 (d, J＝8.9 Hz, 1H, ArH), 7.13 (d, J＝8.4 Hz, 2H, ArH), 5.68 (s, 1H, CH), 2.56 (s, 2H, CH₂), 2.28 (q, J＝16.3 Hz, 2H, CH₂), 1.12 (s, 3H, CH₃), 0.96 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.82, 164.04, 147.78, 143.26, 131.95, 131.54, 131.25, 129.80, 129.10, 128.49, 128.41, 127.12, 125.03, 123.48, 117.09, 117.04, 113.87, 41.43, 34.20, 32.25, 29.30, 27.15; FT-IR (KBr) v: 2957, 1647, 1595, 1487, 1375, 1225, 1013, 845, 837, 750, 534 cm^－1.

  12-(2, 4-Dichlorophenyl)-9, 9-dimethyl-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)-one (4d): White solid, m.p. 174~176 ℃ (lit.^[14] 179~181 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.22 (d, J＝8.5 Hz, 1H, ArH), 7.75 (t, J＝7.7 Hz, 2H, ArH), 7.48 (t, J＝7.2 Hz, 1H, ArH), 7.37 (t, J＝7.4 Hz, 1H, ArH), 7.29 (d, J＝8.9 Hz, 2H, ArH), 7.05 (t, J＝7.0 Hz, 1H, ArH), 7.01~6.94 (m, 1H, ArH), 5.99 (s, 1H, CH), 2.70~2.51 (m, 2H, CH₂), 2.27 (q, J＝16.3 Hz, 2H, CH₂), 1.13 (s, 3H, CH₃), 1.00 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.69, 164.22, 147.72, 142.18, 132.99, 131.72, 131.66, 131.39, 130.01, 129.12, 128.40, 127.65, 127.13, 126.89, 124.95, 123.97, 117.43, 117.07, 113.48, 50.91, 41.52, 33.01, 32.17, 29.36, 27.14; FT-IR (KBr) v: 2949, 1651, 1597, 1472, 1371, 1232, 1184, 941, 812, 744, 478 cm^－1.

  12-(4-Fluorophenyl)-9, 9-dimethyl-9, 10-dihydro-8H-ben- zo[a]xanthen-11(12H)-one (4e): White solid, m.p. 157~159 ℃ (lit.^[25] 156~158 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.92 (d, J＝8.3 Hz, 1H, ArH), 7.78 (t, J＝7.8 Hz, 2H, ArH), 7.45~7.36 (m, 2H, ArH), 7.35~7.27 (m, 3H, ArH), 6.85 (t, J＝8.7 Hz, 2H, ArH), 5.69 (s, 1H, CH), 2.56 (s, 2H, CH₂), 2.28 (q, J＝16.3 Hz, 2H, CH₂), 1.12 (s, 3H, CH₃), 0.96 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.93, 163.95, 147.77, 140.57, 140.53, 131.55, 131.28, 129.94, 129.86, 129.01, 128.47, 127.07, 124.99, 123.55, 117.40, 117.05, 115.14, 114.93, 114.13, 50.90, 41.42, 34.00, 32.26, 29.30, 27.10; FT-IR (KBr) v: 2955, 1651, 1595, 1506, 1375, 1227, 1186, 839, 816, 745, 538, 502 cm^－1.

  9, 9-Dimethyl-12-(2-nitrophenyl)-9, 10-dihydro-8H-ben- zo[a]xanthen-11(12H)-one (4f): Light yellow solid, m.p. 222~224 ℃ (lit.^[21] 223~225 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.56 (d, J＝8.4 Hz, 1H, ArH), 7.90~7.76 (m, 3H, ArH), 7.50~7.38 (m, 2H, ArH), 7.33 (d, J＝8.9 Hz, 1H, ArH), 7.28~7.24 (m, 1H, ArH), 7.22~7.14 (m, 1H, ArH), 7.07~7.04 (m, 1H, ArH), 6.59 (s, 1H, CH), 2.54 (q, J＝17.5 Hz, 2H, CH₂), 2.28~2.21 (m, 2H, CH₂), 1.09 (s, 3H, CH₃), 0.87 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.77, 163.76, 149.31, 148.26, 139.20, 132.72, 131.85, 131.59, 131.11, 129.73, 128.24, 127.61, 127.07, 125.28, 124.71, 124.48, 116.93, 116.24, 113.46, 50.52, 41.49, 32.15, 30.35, 29.13, 27.06; FT-IR (KBr) v: 2961, 1651, 1599, 1528, 1373, 1225, 1026, 831, 820, 764, 517, 419 cm^－1.

  10, 10-Dimethyl-7-(3-nitrophenyl)-10, 11-dihydro-7H-ben-zo[c]xanthen-8(9H)-one (4g): Light yellow solid, m.p. 179~181 ℃ (lit.^[14] 179~180 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.11 (s, 1H, ArH), 7.93 (dd, J＝8.2, 1.2 Hz, 1H, ArH), 7.86 (d, J＝8.3 Hz, 1H, ArH), 7.81 (t, J＝7.0 Hz, 3H, ArH), 7.50~7.31 (m, 4H, ArH), 5.82 (s, 1H, CH), 2.61 (s, 2H, CH₂), 2.29 (q, J＝16.3 Hz, 2H, CH₂), 1.13 (s, 3H, CH₃), 0.95 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.72, 164.53, 148.46, 147.87, 146.80, 134.81, 131.63, 131.00, 129.65, 129.03, 128.70, 127.36, 125.20, 123.25, 123.13, 121.58, 117.22, 116.04, 113.19, 50.80, 41.41, 34.76, 32.31, 29.23, 27.17; FT-IR (KBr) v: 2959, 1651, 1597, 1530, 1375, 1350, 1225, 1177, 812, 748, 683 cm^－1.

  9, 9-Dimethyl-12-(4-nitrophenyl)-9, 10-dihydro-8H-ben- zo[a]xanthen-11(12H)-one (4h): Light yellow solid, m.p. 178~180 ℃ (lit.^[22] 179~180 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.04 (d, J＝8.7 Hz, 2H, ArH), 7.84~7.81 (m, 3H, ArH), 7.51 (d, J＝8.7 Hz, 2H, ArH), 7.46~7.38 (m, 2H, ArH), 7.36 (d, J＝9.0 Hz, 1H, ArH), 5.82 (s, 1H, CH), 2.60 (s, 2H, CH₂), 2.29 (q, J＝16.4 Hz, 2H, CH₂), 1.13 (s, 3H, CH₃), 0.95 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.70, 164.62, 151.86, 147.82, 146.40, 131.61, 131.06, 129.63, 129.36, 128.67, 127.40, 125.26, 123.63, 123.13, 117.09, 116.06, 113.03, 50.81, 41.46, 34.88, 32.26, 29.28, 27.09; FT-IR (KBr) v: 2957, 2359, 1645, 1595, 1516, 1375, 1344, 1236, 1223, 1184, 1144, 831, 750 cm^－1.

  9, 9-Dimethyl-12-p-tolyl-9, 10-dihydro-8H-benzo[a]xant-hen-11(12H)-one: (4i): White solid, m.p. 202~204 ℃ (lit.^[20] 203~205 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.00 (d, J＝8.4 Hz, 1H), 7.75 (t, J＝8.8 Hz, 2H), 7.43 (t, J＝7.1 Hz, 1H), 7.36 (t, J＝7.1 Hz, 1H), 7.31 (d, J＝8.9 Hz, 1H), 7.22 (d, J＝8.0 Hz, 2H), 6.97 (d, J＝7.9 Hz, 2H), 5.66 (s, 1H), 2.56 (s, 2H), 2.27 (q, J＝16.3 Hz, 2H), 2.19 (s, 3H), 1.11 (s, 3H), 0.97 (s, 3H); ¹³C NMR (101 MHz, CDCl₃) δ: 196.98, 163.80, 147.69, 141.88, 135.69, 131.50, 131.43, 128.96, 128.73, 128.39, 128.29, 126.99, 124.87, 123.71, 117.90, 117.07, 114.40, 50.95, 41.43, 34.30, 32.32, 29.29, 27.31, 21.02; FT-IR (KBr) v: 3441, 2952, 2868, 2360, 1649, 1597, 1508, 1372, 1227, 1183, 1028, 813, 758, 618 cm^－1.

  12-(4-Methoxyphenyl)-9, 9-dimethyl-9, 10-dihydro-8H- benzo[a]xanthen-11(12H)-one (4j): White solid, m.p. 206~208 ℃ (lit.^[22] 204~206 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.98 (d, J＝8.4 Hz, 1H, ArH), 7.76 (t, J＝9.3 Hz, 2H, ArH), 7.43 (t, J＝7.1 Hz, 1H, ArH), 7.36 (t, J＝7.4 Hz, 1H, ArH), 7.31 (d, J＝8.9 Hz, 1H, ArH), 7.26~7.23 (m, 2H, ArH), 6.70 (d, J＝8.7 Hz, 2H, ArH), 5.65 (s, 1H, CH), 3.68 (s, 3H, OCH₃), 2.56 (s, 2H, CH₃), 2.27 (q, J＝16.3 Hz, 2H, CH₂), 1.11 (s, 3H, CH₃), 0.97 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 196.99, 163.68, 157.82, 147.72, 137.20, 131.52, 131.43, 129.37, 128.71, 128.38, 126.95, 124.85, 123.72, 117.92, 117.04, 114.46, 113.61, 55.08, 50.96, 41.43, 33.84, 32.27, 29.29, 27.22; FT-IR (KBr) v: 2957, 1647, 1595, 1508, 1379, 1248, 1227, 1180, 1028, 833, 748, 538 cm^－1.

  12-(2-Hydroxyphenyl)-9, 9-dimethyl-9, 10-dihydro-8H-ben-zo[a]xanthen-11(12H)-one (4k): White solid, m.p. 230~232 ℃ (lit.^[21] 230~232 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 9.25 (s, 1H, ArOH), 7.77 (dd, J＝10.0, 5.2 Hz, 2H, ArH), 7.67 (d, J＝8.0 Hz, 1H, ArH), 7.45~7.28 (m, 3H, ArH), 7.05~6.95 (m, 2H, ArH), 6.68~6.54 (m, 2H, ArH), 5.76 (s, 1H, CH), 2.60 (s, 2H, CH₂), 2.38 (q, J＝16.6 Hz, 2H, CH₂), 1.14 (s, 3H, CH₃), 0.99 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 200.58, 166.79, 152.94, 147.88, 132.74, 131.58, 131.16, 129.11, 128.75, 128.24, 127.90, 127.54, 125.27, 123.50, 121.54, 118.86, 117.54, 116.57, 113.99, 50.31, 41.65, 32.41, 29.05, 28.05, 27.25; FT-IR (KBr) v: 2961, 2922, 1630, 1593, 1485, 1379, 1233, 812, 766, 752 cm^－1.

  12-(4-Hydroxyphenyl)-9, 9-dimethyl-9, 10-dihydro-8H- benzo[a]xanthen-11(12H)-one (4l): White solid, m.p. 211~213 ℃ (lit.^[20] 207~209 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.97 (d, J＝8.3 Hz, 1H, ArH), 7.76 (t, J＝9.1 Hz, 2H, ArH), 7.48~7.34 (m, 2H, ArH), 7.31 (d, J＝8.9 Hz, 1H, ArH), 7.16 (d, J＝8.5 Hz, 2H, ArH), 6.59 (d, J＝8.6 Hz, 2H, ArH), 6.24 (s, 1H, ArOH), 5.62 (s, 1H, CH), 2.56 (s, 2H, CH₂), 2.28 (q, J＝16.4 Hz, 2H, CH₂), 1.10 (s, 3H, CH₃), 0.96 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 164.28, 154.32, 147.65, 136.79, 131.57, 131.43, 129.54, 128.75, 128.37, 126.96, 124.91, 123.78, 117.90, 116.99, 115.31, 114.53, 50.92, 41.47, 33.93, 32.33, 29.21, 27.15; FT-IR (KBr) v: 2953, 1651, 1595, 1512, 1373, 1229, 1184, 837, 818, 540 cm^－1.

  12-(4-(Dimethylamino)phenyl)-9, 9-dimethyl-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)-one (4m): Light yellow solid, m.p. 217~219 ℃ (lit.^[20] 218~219 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.03 (d, J＝8.4 Hz, 1H, ArH), 7.76~7.71 (m, 2H, ArH), 7.42 (t, J＝7.2 Hz, 1H, ArH), 7.35 (t, J＝7.3 Hz, 1H, ArH), 7.30 (d, J＝8.9 Hz, 1H, ArH), 7.18 (d, J＝8.7 Hz, 2H, ArH), 6.54 (d, J＝8.7 Hz, 2H, ArH), 5.61 (s, 1H, CH), 2.81 (s, 6H, CH₃), 2.55 (s, 2H, CH₂), 2.34~2.20 (m, 2H, CH₂), 1.11 (s, 3H, CH₃), 0.99 (s, 3H, CH₃); ¹³C NMR (101 MHz, CDCl₃) δ: 197.06, 163.48, 148.89, 147.71, 133.33, 131.56, 131.50, 128.98, 128.43, 128.29, 126.87, 124.74, 123.87, 118.36, 117.02, 114.72, 112.47, 51.00, 41.45, 40.56, 33.60, 32.30, 29.22, 27.42; FT-IR (KBr) v: 2957, 1645, 1611, 1593, 1518, 1377, 1225, 1204, 810, 802 cm^－1.

  12-Phenyl-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)- one (4n): White solid, m.p. 190~192 ℃ (lit.^[22] 190~192 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.96 (d, J＝8.3 Hz, 1H, ArH), 7.80~7.71 (m, 2H, ArH), 7.50~7.30 (m, 5H, ArH), 7.17 (t, J＝7.6 Hz, 2H, ArH), 7.06 (t, J＝7.3 Hz, 1H, ArH), 5.74 (s, 1H, CH), 2.82~2.60 (m, 2H, CH₂), 2.53~2.32 (m, 2H, CH₂), 2.11~1.91 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 196.77, 165.88, 147.68, 142.38, 133.03, 131.78, 131.70, 131.39, 129.98, 129.10, 128.39, 127.65, 127.10, 126.95, 124.92, 123.95, 117.52, 117.02, 114.72, 37.11, 33.08, 27.85, 20.40; FT-IR (KBr) v: 3055, 2955, 1667, 1647, 1593, 1373, 1229, 1190, 955, 831, 816, 702, 530 cm^－1.

  12-(2-Chlorophenyl)-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)-one (4o): White solid, m.p. 245~247 ℃ (lit.^[20] 244~2246 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.21 (d, J＝8.5 Hz, 1H, ArH), 7.75 (t, J＝7.7 Hz, 2H, ArH), 7.48 (dd, J＝11.2, 4.1 Hz, 1H, ArH), 7.37 (t, J＝7.5 Hz, 1H, ArH), 7.31~7.25 (m, 3H, ArH), 7.02 (m, 2H, ArH), 6.01 (s, 1H, CH), 2.89~2.58 (m, 2H, CH₂), 2.46~2.36 (m, 2H, CH₂), 2.17~1.91 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 197.19, 165.59, 147.76, 142.18, 135.74, 131.53, 131.44, 129.71, 129.00, 128.73, 128.35, 127.74, 126.97, 126.39, 126.35, 124.86, 123.73, 117.91, 116.97, 115.76, 109.50, 37.06, 34.24, 27.75, 20.98, 20.30; FT-IR (KBr) v: 2957, 1651, 1591, 1371, 1227, 1190, 999, 957, 833, 766, 752 cm^－1.

  12-(4-Chlorophenyl)-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)-one (4p): Light yellow solid, m.p. 231~232 ℃ (lit.^[18] 228~229 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.88 (d, J＝8.3 Hz, 1H, ArH), 7.78 (dd, J＝8.2, 5.6 Hz, 2H, ArH), 7.45~7.36 (m, 2H, ArH), 7.33 (d, J＝8.9 Hz, 1H, ArH), 7.27 (d, J＝1.7 Hz, 1H, ArH), 7.14~7.12 (m, 2H, ArH), 5.71 (s, 1H), 2.72~2.61 (m, 2H, CH₂), 2.48~2.37 (m, 2H, CH₂), 2.07–1.94 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 197.10, 165.78, 147.77, 143.55, 131.98, 131.53, 131.22, 129.90, 129.13, 128.50, 128.45, 127.14, 125.05, 123.51, 117.08, 117.00, 115.14, 37.04, 34.15, 27.75, 20.29; FT-IR (KBr) v: 3440, 3063, 2956, 2370, 1652, 1591, 1486, 1373, 1228, 1188, 1134, 1093, 1006, 952, 827, 747, 604 cm^－1.

  12-(3-Nitrophenyl)-9, 10-dihydro-8H-benzo[a]xanthen- 11(12H)-one (4q): Light yellow solid, m.p. 234~236 ℃ (lit.^[22] 234~236 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.08 (t, J＝1.9 Hz, 1H, ArH), 7.94 (dd, J＝8.2, 1.3 Hz, 1H, ArH), 7.84~7.80 (m, 4H, ArH), 7.48~7.32 (m, 4H, ArH), 5.84 (s, 1H, CH), 2.86~2.64 (m, 2H, CH₂), 2.52~2.35 (m, 2H, CH₂), 2.14~1.91 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 196.88, 166.20, 148.53, 147.88, 147.02, 134.88, 131.64, 130.99, 129.65, 129.03, 128.68, 127.34, 125.18, 123.32, 123.16, 121.57, 117.14, 116.05, 114.46, 36.93, 34.73, 27.75, 20.27; FT-IR (KBr) v: 2947, 1651, 1526, 1375, 1350, 1223, 1188, 953, 810, 754, 519 cm^－1.

  12-(4-Nitrophenyl)-9, 10-dihydro-8H-benzo[a]xanthen- 11(12H)-one (4r): Light yellow solid, m.p. 236~238 ℃ (lit.^[12] 234~235 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 8.04 (d, J＝8.7 Hz, 2H, ArH), 7.83~7.82 (m, 3H, ArH), 7.51 (d, J＝8.7 Hz, 2H, ArH), 7.47~7.32 (m, 3H, ArH), 5.84 (s, 1H, CH), 2.86~2.63 (m, 2H, CH₂), 2.53~2.33 (m, 2H, CH₂), 2.20~1.86 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 196.86, 166.29, 152.11, 147.82, 131.60, 131.04, 129.63, 129.42, 128.65, 127.39, 125.25, 123.66, 123.16, 117.02, 116.08, 114.31, 36.95, 34.84, 27.79, 20.25; FT-IR (KBr) v: 2940, 1651, 1593, 1518, 1371, 1350, 1227, 1190, 949, 831, 845, 608 cm^－1.

  12-p-Tolyl-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)-one (4s): White solid, m.p. 205~207 ℃ (lit.^[12] 205~217 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.97 (d, J＝8.4 Hz, 1H, ArH), 7.80~7.70 (m, 2H, ArH), 7.37 (m, 3H, ArH), 7.22 (d, J＝8.0 Hz, 2H, ArH), 6.97 (d, J＝7.9 Hz, 2H, ArH), 5.70 (s, 1H, CH), 2.84~2.55 (m, 2H, CH₂), 2.53~2.29 (m, 2H, CH₂), 2.20 (s, 3H, CH₃), 2.11~1.86 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 197.01, 165.58, 147.83, 145.05, 131.53, 131.43, 130.15, 128.82, 128.48, 128.36, 128.26, 126.97, 126.23, 124.88, 123.71, 117.75, 116.96, 115.62, 37.05, 34.66, 27.75, 20.30; FT-IR (KBr) v: 2947, 2359, 1651, 1595, 1508, 1373, 1227, 1188, 953, 818, 745 cm^－1.

  12-(4-Methoxyphenyl)-9, 10-dihydro-8H-benzo[a]xanthen- 11(12H)-one (4t): White solid, m.p. 180~182 ℃ (lit.^[12] 181~182 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.95 (d, J＝8.4 Hz, 1H, ArH), 7.76 (t, J＝8.9 Hz, 2H, ArH), 7.46~7.29 (m, 3H, ArH), 7.23 (t, J＝5.8 Hz, 2H, ArH), 6.70 (d, J＝8.7 Hz, 2H, ArH), 5.69 (s, 1H, CH), 3.69 (s, 3H, OCH₃), 2.75~2.62 (m, 2H, CH₂), 2.52~2.24 (m, 2H, CH₂), 2.16~1.90 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 197.13, 165.38, 157.87, 147.76, 137.48, 131.52, 131.42, 129.43, 128.72, 128.37, 126.94, 124.85, 123.74, 117.93, 116.97, 115.77, 113.66, 55.09, 37.09, 33.78, 27.73, 20.34; FT-IR (KBr) v: 2945, 1651, 1593, 1508, 1377, 1250, 1227, 1190, 1034, 953, 831, 748, 610, 521 cm^－1.

  12-(4-Hydroxyphenyl)-9, 10-dihydro-8H-benzo[a]xanthen-11(12H)-one (4u): White solid, m.p. 267~269 ℃ (lit.^[20] 270~271 ℃); ¹H NMR (400 MHz, CDCl₃) δ: 7.95 (d, J＝8.3 Hz, 1H, ArH), 7.76 (t, J＝9.0 Hz, 2H, ArH), 7.44~7.35 (m, 2H, ArH), 7.32 (d, J＝8.9 Hz, 1H, ArH), 7.18 (d, J＝8.5 Hz, 2H, ArH), 6.62 (d, J＝8.5 Hz, 2H, ArH), 5.67 (s, 1H, CH), 2.88~2.57 (m, 2H, CH₂), 2.54~2.30 (m, 2H, CH₂), 2.10~1.91 (m, 2H, CH₂); ¹³C NMR (101 MHz, CDCl₃) δ: 189.32, 153.96, 147.72, 137.48, 131.53, 129.66, 128.75, 128.37, 126.94, 124.87, 123.75, 117.86, 116.96, 115.76, 115.16, 37.07, 33.81, 29.32, 27.74, 20.33; FT-IR (KBr) v: 3327, 1634, 1591, 1508, 1381, 1231, 1196, 1003, 951, 835, 816, 841, 610, 501 cm^－1.

  Supporting Information The copies of FT-IR, and NMR spectra for β-CD-AIL and some selected tetrahydrobenzo[a]xanthen-11-ones. The Supporting Information is available free of charge via the Internet at http://sioc-journal.cn/.

  
  
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  Scheme 1  Preparation of tetrahydrobenzo[a]xanthen-11-ones

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  Scheme 2  Synthesis of β-CD-AIL

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  Figure 1  FT-IR spectra of (i) β-CD and (ii) β-CD-AIL

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  Figure 2  ¹H NMR spectra of β-CD, β-CD-DEA and β-CD-AIL in D₂O

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  Figure 3  Reusability of β-CD-AIL for the synthesis of 4a

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  Scheme 3  Plausible mechanism for the β-CD-AIL catalyzed this MCR in water

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  Table 1.  Optimization of reaction conditions for the synthesis of 4a^a

  Entry	Solvent	Catalyst	Cat./ mol%	T/℃	Time/ min	Yieldb/%
  1	H2O	—	—	r.t.	120	NRc
  2	H2O	—	—	80	120	NRc
  3	H2O	β-CD-AIL	3	r.t.	120	24
  4	H2O	β-CD-AIL	3	50	60	81
  5	H2O	β-CD-AIL	3	80	30	92
  6	H2O	β-CD-AIL	3	100	30	91
  7	H2O	β-CD-AIL	1	80	30	79
  8	H2O	β-CD-AIL	5	80	30	92
  9	Solvent-free	β-CD-AIL	3	80	30	85
  10	CH3CH2OH	β-CD-AIL	3	80	30	88
  11	ClCH2CH2Cl	β-CD-AIL	3	80	30	72
  12	THF	β-CD-AIL	3	80	30	68
  13	CH3CN	β-CD-AIL	3	80	30	56
  14	DMF	β-CD-AIL	3	80	30	78
  15	H2O	β-CD	3	80	30	10
  16	H2O	AILd	3	80	30	76
  17	H2O	β-CD+AIL	3+3	80	30	81
  a Reaction condition: benzaldehyde (2 mmol), β-naphthol (2 mmol) and dimedone (2 mmol), solvent-free or solvent (3 mL). b Isolated yield. c No reaction was observed. d AIL: N, N, N-triethyl-N-(3-sulfopropyl)ammonium hydrogen sulfate.

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  Table 2.  Synthesis of tetrahydrobenzo[a]xanthen-11-ones catalyzed by β-CD-AIL in water^a

  Entry	Ar	R1	Compd.	Time/min	Yieldb/%
  1	C6H5	CH3	4a	30	92
  2	2-Cl-C6H4	CH3	4b	30	90
  3	4-Cl-C6H4	CH3	4c	25	94
  4	2, 4-Cl2-C6H4	CH3	4d	30	88
  5	4-F-C6H4	CH3	4e	20	92
  6	2-NO2-C6H4	CH3	4f	25	91
  7	3-NO2-C6H4	CH3	4g	25	90
  8	4-NO2-C6H4	CH3	4h	20	95
  9	4-CH3-C6H4	CH3	4i	30	91
  10	4-CH3O-C6H4	CH3	4j	35	88
  11	2-HO-C6H4	CH3	4k	30	82
  12	4-HO-C6H4	CH3	4l	30	85
  13	4-N(CH3)2-C6H4	CH3	4m	30	90
  14	C6H5	H	4n	30	90
  15	2-Cl-C6H4	H	4o	30	89
  16	4-Cl-C6H4	H	4p	25	92
  17	3-NO2-C6H4	H	4q	25	91
  18	4-NO2-C6H4	H	4r	20	93
  19	4-CH3-C6H4	H	4s	30	90
  20	4-CH3O-C6H4	H	4t	40	86
  21	4-OH-C6H4	H	4u	40	83
  a Reaction condition: aldehyde (2 mmol), β-naphthol (2 mmol), dimedone or 1, 3-cyclohexanedione (2 mmol), β-CD-AIL (0.06 mmol), H2O (3 mL), 80 ℃. b Isolated yield.

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