Stereoselective ozonolysis of TMS-substituted allylic alcohol derivatives and synthesis of 14R,15S- and 14S,15S-diHETE

Abstract

Ozonolysis of TMS-substituted olefins produces α-carbonyl TMS peroxides without cleavage of the CC bond. Herein, stereochemistry in the ozonolysis was studied using silyl derivatives of (E)- and (Z)-(1-TMS)alk-1-en-3-ols. The (E)-isomers afforded the anti-3-siloxy-2-(TMS-oxy)aldehydes as the major stereoisomer (anti/syn = 3–9 : 1) after reductive work-up with Ph₃P. In contrast, Z-olefins selectively gave the syn isomers with syn/anti ratios of 4–19 : 1. Facial selection was speculated based on the Cieplak effect. This ozonolysis was successfully applied for the synthesis of 14R,15S- and 14S,15S-diHETEs (anti and syn isomers, respectively) in enantioenriched forms.