Remote acyclic diastereocontol involving a bicyclic metal chelate. High 1,5 asymmetric induction in the hydride reduction of δ-hydroxy ketones
作者:Han-Cheng Zhang、Michael J. Costanzo、Bruce E. Maryanoff
DOI:10.1016/s0040-4039(00)73275-8
日期:1994.7
A variety of reducing agents was explored to effect stereoselective reduction of acyclic δ-hydroxy ketone 3a; R-Alpine-Hydride provided high anti stereoselectivity (anti:syn = 7:1). Reduction of 3b in CH2Cl2 with R-Alpine-Hydride or Zn(BH4)2 afforded impressive anti stereoselectivity: 10:1 and 13:1, respectively. The stereochemical outcome is attributed to a bicyclic metal-chelate species (viz. 10)
探索了多种还原剂以实现无环δ-羟基酮3a的立体选择性还原。R-高山-氢化物提供了高的抗立体选择性(anti:syn = 7:1)。用R-高山-氢化物或Zn(BH 4)2还原CH 2 Cl 2中的3b可获得令人印象深刻的抗立体选择性:分别为10:1和13:1。立体化学结果归因于双环金属螯合物物种(即10)。