Synthetic approaches to phomactins: on the stereoselectivity of some [2,3]-Wittig rearrangements
作者:Timothy J. Blackburn、Michael J. Kilner、Eric J. Thomas
DOI:10.1016/j.tet.2015.04.005
日期:2015.9
On treatment with n-butyllithium, 4-alkoxy- and 4-silyloxy-2-(tributylstannylmethoxymethyl)-1,6-dimethyl-1-(phenylsulfonylmethyl)cyclohex-2-enes undergo tin–lithium exchange followed by [2,3]-Wittig rearrangements to give 3-alkoxy- and 3-silyloxy-2-hydroxymethyl-5,6-dimethyl-1-methylene-6-(phenylsulfonylmethyl)cyclohexanes in which the 2-hydroxymethyl and 6-phenylsulfonylmethyl residues are cis-disposed
在用正丁基锂处理后,对4-烷氧基和4-甲硅烷氧基-2-(三丁基锡烷基甲氧基甲基)-1,6-二甲基-1-(苯基磺酰基甲基)环己-2-烯进行锡-锂交换,然后[2,3] -Wittig重排得到3-烷氧基-和3-甲硅烷氧基-2-羟基甲基-5,6-二甲基-1-亚甲基-6-(苯磺酰基甲基)环己烷,其中2-羟基甲基和6-苯基磺酰基甲基残基顺式-六元环。相反,相应的1-(苯基硫烷基甲基)环己烯主要给出亚甲基环己烷,其中2-羟基甲基和6-苯基硫烷基甲基围绕六元环反位。该立体选择性不依赖于烷氧基或甲硅烷氧基取代基的性质以及在C4处的构型。3-叔丁基二苯基甲硅烷氧基-1-亚甲基-6-(苯磺酰基甲基)环己烷被转化为phoactactins的大环前体。