Total synthesis of epothilones using functionalised allylstannanes for remote stereocontrol
作者:Nathaniel Martin、Eric J. Thomas
DOI:10.1039/c2ob26310f
日期:——
converted into (2S,9S,6Z)-2,6-dimethyl-9,10-(dimethylmethylene)dioxydec-6-en-1-ol 41 by regioselective alkene manipulation, ester reduction and cleavage of the resulting terminal diol 40 with a reductive work-up. The second synthesis involved the tin(IV) bromide mediated reaction between the stannane 20 and (3S)-4-(4-methoxybenzyloxy)-3-methylbutanal 44 that gave (2S,7S,9S,4Z)-1-tert-butyldimethylsilyloxy-5
埃博霉素D 2的C(7)–C(16)片段41的两个合成是基于锡(IV)溴化物介导的5,6-二官能化的-2--2-锡基锡与醛的反应而开发的。在第一合成中,使(5 S)-6-叔丁基二甲基甲硅烷氧基-5-羟基-2-甲基己二烯基-2-三丁基锡锡烷20与(E)-丁-2-烯醛反应,得到(2 S, 7 - [R,4 ž,8 ë)-1-叔-butyldimethylsilyloxy -5- methyldeca -4,8-二烯-2,7-二醇26含有约 其(7 S)-epimer。脱甲硅烷基化后,将结晶的(2 S,7 R)-三醇32作为其乙交酯33保护并酯化,得到(4-甲氧基苄氧基)乙酸酯34。该酯的爱尔兰-克莱森重排得到甲基(2 R,3 S,10 S,4 E,7 Z)-3,7-二甲基-10,11-(二甲基亚甲基)二氧基-2-(4-甲氧基苄氧基) -4,7-二烯酸酯35转化为(2 S,9 S,6 Z)-2,6-二甲基-9