Stereoselectivity in the Birch reduction of 2-furoic acid derivatives
作者:Timothy J Donohoe、Madeleine Helliwell、Clare A Stevenson、Tamara Ladduwahetty
DOI:10.1016/s0040-4039(98)00361-x
日期:1998.5
The preparation and Birchreduction of chiral 3-methyl-2-furoic acid derivatives is described. Using a C2 symmetrical amine as a chiral auxiliary, very high levels of sterochemical control could be obtained. Moreover, the auxiliary could be removed conveniently by heating in 6M HCl to liberate a carboxylic acid of high enantiomeric purity. The relative stereochemistry of the Birch reduced amides (and
The synthesis of (−)-cis- and (−)-trans-crobarbatic acid
作者:Timothy J Donohoe、Clare A Stevenson、Madeleine Helliwell、Ranah Irshad†、Tamara Ladduwahetty
DOI:10.1016/s0957-4166(99)00097-x
日期:1999.4
The synthesis of both cis- and trans-crobarbatic acid is reported. The five-step sequence proceeds in high yield and with control of both relative and absolute stereochemistry. The key step in the synthesis is the Birch reductive alkylation of a chiral furoic acid which sets the absolute stereochemistry of the products. The stereochemistry of the compounds described was proven unambiguously by X-ray crystallography on one synthetic intermediate and on trans-crobarbatic acid. (C) 1999 Elsevier Science Ltd, All rights reserved.