Studies for the enantiocontrolled preparation of substituted tetrahydropyrans: applications for the synthesis of leucascandrolide A macrolactone
作者:David R. Williams、Scott V. Plummer、Samarjit Patnaik
DOI:10.1016/j.tet.2011.05.020
日期:2011.7
Strategies for the stereocontrolled preparations of 2,6-cis- and 2,6-trans-substituted tetrahydropyrans have been devised. These studies have explored methodology for asymmetric induction in S-E' reactions using chiral 1,3,2-diazaborolidine controllers. Reactions with aldehydes at -78 degrees C yield nonracemic 1,5-diols for chemoselective internal backside displacements. This concept is developed as a flexible and reliable strategy in studies toward leucascandrolide A macrolactone 2 via the sequential applications of S-E' reactions leading to the C-1-C-9 aldehyde 14, and the bis-tetrahydropyran 59, respectively. (C) 2011 Elsevier Ltd. All rights reserved.