ChemInform Abstract: Stereoselective Synthesis of Contiguously-Substituted Butyrolactones Based on the Cyclic Allylsulfonium Ylide Rearrangement.
Abstract
Phenyl propargyl sulfide (I) is activated via formation of the ethyl Grignard compound to react with the aldehydes (II), forming the carbinols (III) which are O-acylated with ethyl malonyl chloride (IV) to give the esters (V).
ChemInform Abstract
Phenyl propargyl sulfide (I) is activated via formation of the ethyl Grignard compound to react with the aldehydes (II), forming the carbinols (III) which are O-acylated with ethyl malonyl chloride (IV) to give the esters (V). Hydrogenation in the presence of a Lindlar catalyst yields the Z-olefins (VI) which are diazotized to produce the diazomalonates (VIII). These compounds undergo ring closure in the presence of rhodium catalysts to give the butyrolactones (IX). In order to investigate the stereochemistry, NOE experiments with the methoxytetrahydrofuran (XII), derived from (IXa), are performed.
