Asymmetrization of all-cis-3,5-dihydroxy-1-(methoxycarbonyl)cyclohexane and of the 4-methyl and 4-ethyl substituted homologues
摘要:
Enantiomerically pure mono acylated derivatives of cis,cis-3, 5-dihydroxy-1-(methoxycarbonyl)cyclohexane 1, all-cis-3,5-dihydroxy-4-methyl-1-(methoxycarbonyl)cyclohexane 2 and all-cis-3,5-dihydroxy-4-ethyl-1-(methoxycarbonyl)cyclohexane 3 were obtained upon lipase catalyzed asymmetrization. PPL-catalyzed transesterification of 1 with vinyl acetate led in high yield to the (S)-monoacetate (+)-13. With substrates 2 and 3 this process was slower and gave the (R)-monoacetates (-)-14 and (-)-15; the best results were obtained with SAM II lipase. On the other hand, enantiotoposelective hydrolysis of their diacetates and especially dibutyrates gave useful results only for the 4-substituted substrates and produced the (S)-monoesters. (C) 2000 Elsevier Science Ltd. All rights reserved.
Asymmetrization of all-cis-3,5-dihydroxy-1-(methoxycarbonyl)cyclohexane and of the 4-methyl and 4-ethyl substituted homologues
摘要:
Enantiomerically pure mono acylated derivatives of cis,cis-3, 5-dihydroxy-1-(methoxycarbonyl)cyclohexane 1, all-cis-3,5-dihydroxy-4-methyl-1-(methoxycarbonyl)cyclohexane 2 and all-cis-3,5-dihydroxy-4-ethyl-1-(methoxycarbonyl)cyclohexane 3 were obtained upon lipase catalyzed asymmetrization. PPL-catalyzed transesterification of 1 with vinyl acetate led in high yield to the (S)-monoacetate (+)-13. With substrates 2 and 3 this process was slower and gave the (R)-monoacetates (-)-14 and (-)-15; the best results were obtained with SAM II lipase. On the other hand, enantiotoposelective hydrolysis of their diacetates and especially dibutyrates gave useful results only for the 4-substituted substrates and produced the (S)-monoesters. (C) 2000 Elsevier Science Ltd. All rights reserved.
A Convenient, Large Scale Synthesis of<i>trans</i>-(+)-Sobrerol
作者:Qiuan Wang、Yanlin Li、Qingqi Chen
DOI:10.1081/scc-120021040
日期:2003.7
A convenient and highly efficient synthesis of optically pure trans(+)-sobrerol (1), starting from methyl 3,5-dihydroxy-4-methyl benzoate 2 in 8 steps with overall yield 26%, is reported. The key intermediate 4 is prepared in remarkably high yield by selectively esterification of 3 using lipase as catalyst. A critical step to stereoselectively inverse the configuration of 7 is realized under Mistunobu conditions.
Asymmetrization of all-cis-3,5-dihydroxy-1-(methoxycarbonyl)cyclohexane and of the 4-methyl and 4-ethyl substituted homologues
作者:Yurui Zhao、Yusheng Wu、Pierre De Clercq、Maurits Vandewalle、Philippe Maillos、Jean-Claude Pascal
DOI:10.1016/s0957-4166(00)00339-6
日期:2000.10
Enantiomerically pure mono acylated derivatives of cis,cis-3, 5-dihydroxy-1-(methoxycarbonyl)cyclohexane 1, all-cis-3,5-dihydroxy-4-methyl-1-(methoxycarbonyl)cyclohexane 2 and all-cis-3,5-dihydroxy-4-ethyl-1-(methoxycarbonyl)cyclohexane 3 were obtained upon lipase catalyzed asymmetrization. PPL-catalyzed transesterification of 1 with vinyl acetate led in high yield to the (S)-monoacetate (+)-13. With substrates 2 and 3 this process was slower and gave the (R)-monoacetates (-)-14 and (-)-15; the best results were obtained with SAM II lipase. On the other hand, enantiotoposelective hydrolysis of their diacetates and especially dibutyrates gave useful results only for the 4-substituted substrates and produced the (S)-monoesters. (C) 2000 Elsevier Science Ltd. All rights reserved.