Convergent diastereoselective preparation of adjacent quaternary stereocenters in an acyclic system
作者:Tom Mejuch、Bishnu Dutta、Mark Botoshansky、Ilan Marek
DOI:10.1039/c2ob25121c
日期:——
3-disubstituted allylmetal species with ketones allow the preparation of allylic vicinal diol derivatives in good yields with excellent diastereomeric ratios from commercially available alkynes. Two adjacent quaternary centers are formed with the concomitant formation of three new carbon–carbon bonds in a single-pot operation in an acyclic system. The bulky substituent of the ketone occupies a pseudo-axial position
所得的立体定义的3,3-二取代的烯丙基金属物种与酮的碳金属合-锌同源-烯丙基化反应可从商业上的炔烃中以优异的非对映异构体比例以高收率制备烯丙基邻位二醇衍生物。形成两个相邻的四元中心,并在无环系统的单锅操作中同时形成三个新的碳-碳键。酮的庞大取代基在Zimmerman-Traxler过渡态中占据伪轴向位置。