Cycloaddition of 3-O-allyl-1,2-isopropylidene N-Ph nitrones afforded appreciably increased yields of oxepanes compared to the corresponding N-Me or N-Bn nitrones. Higher yields permitted some useful further transformations of the oxepanes. (c) 2008 Elsevier Ltd. All rights reserved.
Stereoselective Synthesis of Chiral Oxepanes and Pyrans through Intramolecular Nitrone Cycloaddition in Organized Aqueous Media
作者:Amrita Chatterjee、Pranab K. Bhattacharya
DOI:10.1021/jo051414j
日期:2006.1.1
A highly stereoselective surfactant-catalyzed intramolecularnitrone (formed by dehydration in water) cycloaddition in aqueous media leading to exclusive formation of a single isomer is reported. Either oxepane or pyran is formed from 3-O-allyl furanoside derivatives, which constitute the framework of a large number of biologically active compounds. Therefore, the environmentally friendly, efficient