Gleason-type chiralauxiliaries were used for the synthesis of a novel class of sulfonium salts, obtained via methylation of the sulfide with Meerwein's salt. The salts were reacted with aldehydes under basic conditions to provide epoxy amides, which were reduced to their corresponding epoxy alcohols in excellent enantiomeric excesses. Interestingly, it was feasible to synthesize both enantiomeric
A Practical Chiral Bicyclic Thioglycolate Lactam Auxiliary for Stereoselective Quaternary Carbon Formation
作者:Azélie Arpin、Jeffrey M. Manthorpe、James L. Gleason
DOI:10.1021/ol060106k
日期:2006.3.1
[reaction: see text] Chiralbicyclic thioglycolate lactams may be prepared in three steps from inexpensive commercial materials. The resulting lactams may be alkylated three times, twice using basic enolization and once using reductive enolization, to form alpha-quaternary carboxylic acid derivatives in high yield and with high diastereoselectivity. The alkylation products may be cleaved under either