Stereo-divergent asymmetric total synthesis of avenaciolide and isoavenaciolide. Complete reversal of stereoselectivity in reduction of 2-vinyl aldols with / without trimethylsilyl directing group
Stereo-divergent: asymmetric total synthesis of avenaciolide and isoavenaciolide was achieved via 1,2-rearrangement of chiral epoxyalcohol derivatives, where complete reversal of stereoselectivity with / without the TMS-directing group in the reduction of 2-vinyl aldols was used as the key branching point.
Stereo-defined 2-vinyl-1,3-diols are synthesized by the reduction of aldol derivatives bearing α-trimethylsilylvinyl group at C(2) (LiBEt3H / THF, −78°C), which proceeds highlystereoselectively to give 1,2-syn isomer as the sole product.
立体定义的2-乙烯基-1,3-二醇是通过在C(2)(LiBEt 3 H / THF,-78°C)下还原带有α-三甲基甲硅烷基乙烯基的羟醛衍生物而合成的,立体选择性高,得到1 ,2-syn异构体为唯一产物。
Catalytic version of epoxy silyl ether rearrangements
Catalytic version of epoxy silyletherrearrangements using Me3SiX (X=I, OTf: 5 mol %) as the Lewis acid catalyst is reported, which leads to generally higher yields of the aldol products than stoichiometric version.