Stereospecific intramolecular Michael addition to (−)-carvone based on temporary sulfur connection
作者:Mario D Bachi、Yaroslav V Bilokin、Artem Melman
DOI:10.1016/s0040-4039(98)00327-x
日期:1998.5
xocyclohexyl)acetic acid methyl ester (21) in a process involving the following stages: i) addition of ClSCH2CO2Me to the isopropenyl group of 7 to give, after oxidation, [1-chloro-2(RS)-(1(R),4-methyl-5-oxocyclohex-3-enyl)propane-2-sulfonyl]acetic acid methyl ester (18); ii) intramolecular Michael addition of 18 to afford (1S,2S,4(RS),5R,8S)-4-chloromethyl-4,8-dimethyl-3,3,7-trioxo-3-thiabicyclo [3
将乙酸残基(CH 2 CO 2 Me)立体选择性地连接至(-)-香芹酮(7),得到(1 R,2 S,5 R)-(5-异丙烯基-2-甲基-3-氧代环己基)乙酸酸甲酯(21),该过程包括以下步骤:i)将ClSCH 2 CO 2 Me加到7的异丙烯基上,在氧化后得到[1-氯-2(RS)-(1(R)] ,4-甲基-5-氧代环己基-3-烯基)丙烷-2-磺酰基]乙酸甲酯(18);ii)分子内迈克尔加18以提供(1 S,2 S,4(RS),5 R,8 S)-4-氯甲基-4,8-二甲基-3,3,7-三氧代-3-硫代双环[3.3.1]壬烷-2-羧酸甲酯(20); iii)通过串联还原性消除(包括硫的挤出)和异丙烯基的还原(20→21)使乙酸部分断开。