Modular synthesis of allyl vinyl ethers for the enantioselective construction of functionalized quaternary stereocenters

Abstract

A flexible synthesis of allyl vinyl ethers, precursors of functionalized quaternary stereocenters, was developed by employing a regioselective Petasis olefination of haloallyl oxalates and subsequent cross-coupling with alkyl- and aryl boronic acids.

Formation of Enol Ethers by Radical Decarboxylation of α-Alkoxy β-Phenylthio Acids

“…6 Another powerful method is the methylenation of an ester carbonyl with the Tebbe or Petasis reagents. 7 This procedure can be combined with ring-closing metathesis to afford cyclic enol ethers. 8 Reaction of aldehydes and ketones with Wittig or Horner− Wadsworth−Emmons reagents carrying an alkoxy group also gives enol ethers.…”

“…A very versatile route is the Birch reduction or palladium-mediated reduction of vinyl phosphate ethers, which are available from esters and lactones . Another powerful method is the methylenation of an ester carbonyl with the Tebbe or Petasis reagents . This procedure can be combined with ring-closing metathesis to afford cyclic enol ethers .…”