Concise, Stereoselective Syntheses of <i>cis</i>-Nemorensic Acid and 4-Hydroxy-<i>cis</i>-nemorensic Acid via Tandem Carbonyl Ylide Formation−Cycloaddition

Abstract

[reaction: see text] 1,3-Dipolar cycloaddition of propargyl bromide with the carbonyl ylide derived from 6-diazoheptane-2,5-dione is the key step in concise syntheses of cis-nemorensic acid and 4-hydroxy-cis-nemorensic acid.