The new concept for stereocontrol at a spiroacetalic centre in thermodynamically controlled spiroacetalization, based on the operation of the Î2 effect, allows the synthesis of (-)-Talaromycin A (3R,4S,6R,9R)-9-ethyl-4- hydroxy-3-hydroxymethyl-1,7-dioxaspiro[5.5]undecane} in a linear sequence from D-glucose with an overall diastereoselectivity > 97%.
热力学控制螺
缩醛化中螺
缩醛中心立体控制的新概念,基于α2效应的操作,允许合成(-)-Talaromycin A (3R,4S,6R,9R)-9-乙基-
4-羟基-3-羟甲基-1,7-二氧杂螺[5.5]
十一烷},以
D-葡萄糖为线性序列,总体非对映选择性 > 97%。