Total Synthesis of (−)-Bitungolide F and Determination of Its Absolute Stereochemistry
作者:Subhash Ghosh、Soma Uday Kumar、J. Shashidhar
DOI:10.1021/jo7023152
日期:2008.2.1
A highly convergent total synthesis of bitungolide F leading to the assignment of its absolute stereochemistry is described. The key steps include a Horner−Wadsworth−Emmons olefination to construct the C7−C8 bond, a Wittig reaction to introduce the conjugate E,E-olefinic moiety in the molecule, and finally a ring-closing metathesis reaction to construct the six-membered α,β-unsaturated δ-lactone of
描述了高度收敛的bitungolide F的全合成,导致其绝对立体化学的赋值。关键步骤包括霍纳-沃兹沃思-埃蒙斯烯烃化反应以构建C7-C8键,维蒂希反应以在分子中引入共轭E,E-烯烃部分,最后是闭环易位反应以构建六元环分子的α,β-不饱和δ-内酯。使用Crimmins的方案,修改后的Evans的syn- aldol反应用于在C4和C5中心安装立体化学。使用Evans规程通过C9酮的羟基直接还原法引入C9处的立体化学。