In(OTf)3 plays the role of a Lewis acid catalyst in the Pechmann condensation of phenols with β-ketoesters under solvent-free conditions to give coumarin derivatives. This novel and inexpensive method has advantages ...In(OTf)3 plays the role of a Lewis acid catalyst in the Pechmann condensation of phenols with β-ketoesters under solvent-free conditions to give coumarin derivatives. This novel and inexpensive method has advantages such as short reaction time, excellent product yields, and avoids the use of organic solvents in agreement with green chemistry principles. Catalyst loadings can be as low as 1 mol% to give high yields of the corresponding coumarins at 80 °C. The catalyst can be recovered after the reaction, and reused with only a slight decrease in the yield.展开更多
In the presence of catalytic amount of In（OTf）3 （10 mol%）, a series of aldimines reacted with tetraallyltin in a 2：1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom effici...In the presence of catalytic amount of In（OTf）3 （10 mol%）, a series of aldimines reacted with tetraallyltin in a 2：1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom efficiency was achieved under mild reaction conditions and a new protocol （allyl）4Sn/In（OTf）3 for simple imines was developed.展开更多
A simple, environmental-friendly, and practical method for the synthesis of benzodiazepine derivatives through a reaction of substituted o-phenylenediamines with alkyl propiolates has been developed. The reactions gen...A simple, environmental-friendly, and practical method for the synthesis of benzodiazepine derivatives through a reaction of substituted o-phenylenediamines with alkyl propiolates has been developed. The reactions generated the 1,5-benzodiazepines in good to excellent yields in the presence of catalytic amount of In（OTf）3 under sol- vent-free reaction conditions.展开更多
A general and practical procedure for the syntheses of 3,4 dihydropyrimidine 2(1 H ) thiones by a one pot condensation of aldehyde, β ketoester or β diketone and thiourea using La (OTf) 3 as the catalyst ...A general and practical procedure for the syntheses of 3,4 dihydropyrimidine 2(1 H ) thiones by a one pot condensation of aldehyde, β ketoester or β diketone and thiourea using La (OTf) 3 as the catalyst is described. Mild reaction conditions, excellent yields as well as the environmentally friendly character of La(OTf) 3 make it an important alternative to the classic acid catalyzed Biginelli's reaction.展开更多
O,O＇Diethyl acetals were prepared in high yields under mild conditions via the reaction of triethyl orthoformate with aldehydes and ketones in absolute ethanol in the presence of as low as 0.1 tool% of Yb（OTf）3. Us...O,O＇Diethyl acetals were prepared in high yields under mild conditions via the reaction of triethyl orthoformate with aldehydes and ketones in absolute ethanol in the presence of as low as 0.1 tool% of Yb（OTf）3. Using the same catalyst in THF-H2O, these O,O＇-diethyl acetals could be converted to the corresponding carbonyl compounds efficiently. This new protection-deprotection protocol presents the advantages of ease of execution, high efficiency and good chemoselectivity.展开更多
文摘In(OTf)3 plays the role of a Lewis acid catalyst in the Pechmann condensation of phenols with β-ketoesters under solvent-free conditions to give coumarin derivatives. This novel and inexpensive method has advantages such as short reaction time, excellent product yields, and avoids the use of organic solvents in agreement with green chemistry principles. Catalyst loadings can be as low as 1 mol% to give high yields of the corresponding coumarins at 80 °C. The catalyst can be recovered after the reaction, and reused with only a slight decrease in the yield.
基金the National Natural Science Foundation of China(Nos.20421202,20372033)for financialsupport.
文摘In the presence of catalytic amount of In（OTf）3 （10 mol%）, a series of aldimines reacted with tetraallyltin in a 2：1 molar ratio to afford the corresponding homoallylic amines in good yields. The good atom efficiency was achieved under mild reaction conditions and a new protocol （allyl）4Sn/In（OTf）3 for simple imines was developed.
基金Project supported bythe National Natural Science Foundation of China（Nol 20972057）.
文摘A simple, environmental-friendly, and practical method for the synthesis of benzodiazepine derivatives through a reaction of substituted o-phenylenediamines with alkyl propiolates has been developed. The reactions generated the 1,5-benzodiazepines in good to excellent yields in the presence of catalytic amount of In（OTf）3 under sol- vent-free reaction conditions.
文摘A general and practical procedure for the syntheses of 3,4 dihydropyrimidine 2(1 H ) thiones by a one pot condensation of aldehyde, β ketoester or β diketone and thiourea using La (OTf) 3 as the catalyst is described. Mild reaction conditions, excellent yields as well as the environmentally friendly character of La(OTf) 3 make it an important alternative to the classic acid catalyzed Biginelli's reaction.
基金Project supported by the National Natural Science Foundation of China （Nos. 20425205, 20321202） and the Shanghai Municipal Commission of Science and Technology （Nos. 04DZ 14901, 06QH 14016）.
文摘O,O＇Diethyl acetals were prepared in high yields under mild conditions via the reaction of triethyl orthoformate with aldehydes and ketones in absolute ethanol in the presence of as low as 0.1 tool% of Yb（OTf）3. Using the same catalyst in THF-H2O, these O,O＇-diethyl acetals could be converted to the corresponding carbonyl compounds efficiently. This new protection-deprotection protocol presents the advantages of ease of execution, high efficiency and good chemoselectivity.
