Vinyl anion equivalents. Part 3. Diastereoselective allylation of 2-phenylseleno-3-trialkylsilyl- and 2-phenylthio-3-(tributylstannyl)cyclopentanone enolates

Abstract

Diastereoselective allylation of enolates derived from 2-phenylseleno(thio)cyclopent-2-enone by conjugate addition of a silyl or stannyl nucleophile has been investigated. All allylated compounds are formed in high cis preference. Calculation of the energies of the formation and the stereochemical outcome at equilibrium show higher stability of the cis compounds than of the corresponding trans isomers. The efficient transformation of the allylated products into 2-allylcyclopent-2-enone is also described.