Construction of Multiple, Contiguous Quaternary Stereocenters in Acyclic Molecules by Lithiation-Borylation
作者:Charlotte G. Watson、Angelica Balanta、Tim G. Elford、Stéphanie Essafi、Jeremy N. Harvey、Varinder K. Aggarwal
DOI:10.1021/ja509029h
日期:2014.12.17
construction of two quaternary centers, this methodology fails. Instead, using mixed boranes (tBuBMe2), the synthesis of adjacent quaternary stereogenic centers with full stereocontrol was successful. The process can be repeated two or three times in one pot leading to carbon chains bearing multiple contiguous quaternary stereogenic centers. The boranes were converted into tertiary alcohols or C-tertiary amines
氨基甲酸酯锂化和硼酸化为硼试剂的同系化提供了一种强有力的方法。然而,当应用于受阻系统(带有 tBu-硼酸酯的二级氨基甲酸酯)以构建两个四元中心时,这种方法失败了。相反,使用混合硼烷 (tBuBMe2),具有完全立体控制的相邻四元立体中心的合成是成功的。该过程可以在一锅中重复两到三次,从而产生带有多个连续四元立体中心的碳链。使用氯胺将硼烷转化为叔醇或 C-叔胺。通过计算确定烷基对 Me 基团迁移的高选择性的起源。