Studies towards 1,3-diol units starting from syn β-hydroxy acylsilanes
摘要:
Three complementary strategies have been explored to obtain stereodefined 1,3 diols starting from easily accessible syn beta-hydroxy acylsilanes: fluoride induced migrations of substituents on silicon, a Grignard addition followed by protodesilylation and Tischenko-type reactions. Preliminary data on scope and limitations of these processes are presented. (C) 2013 Elsevier Ltd. All rights reserved.
Stereoselective aldol condensations via boron enolates
作者:D. A. Evans、J. V. Nelson、E. Vogel、T. R. Taber
DOI:10.1021/ja00401a031
日期:1981.6
carboxylic acid derivatives with dialkylboryl triflates in the presence of a tertiary amine and the subsequent aldol condensations of these boron enolates was conducted. The stereochemistry of the enolates formed from acyclic ketones was found to be dependent on the structure of the ketone, the dialkylboryl triflate, and the tertiary amine. A mechanism for the enolization involving initial coordination of
The redox isomerization processes and tandem isomerization-aldolization reactions, mediated by nickel catalysts, offer new versatile entries to acylsilanes. For the second reaction, high diastereoselectivities, up to 98:2, have been obtained with bulky substituents on silicon.
Acyllithium to lithium enolate conversion by a 1,2-silicon shift. A shortcut to acylsilane enolates