Highly <i>Z</i>-Selective Horner–Wadsworth–Emmons Olefination Using Modified Still–Gennari-Type Reagents

Abstract

In this report, new, easily accessible reagents for highly Z-selective HWE reactions are presented. Alkyl di-(1,1,1,3,3,3-hexafluoroisopropyl)phosphonoacetates, structurally similar to Still–Gennari type reagents, were tested in HWE reactions with a series of various aldehydes. Very good Z-selectivity (up to a 98:2 Z:E ratio) was achieved in most cases along with high yields. Application of the new reagents may be a valuable, practical alternative to the well-established Still–Gennari or Ando Z-selective carbonyl group olefination protocols.

Keywords

• HWE reaction
• Still-Gennari olefination
• Ando olefination
• stereoselective synthesis
• <i>Z</i>-selectivity
• Wittig reaction