Catalytic asymmetric synthesis of chiral allylic esters

A broadly useful catalytic enantioselective synthesis of branched allylic esters from prochiral (Z)-2-alkene-1-ols has been developed. The starting allylic alcohol is converted to its trichloroacetimidate intermediate by reaction with trichloroacetonitrile, either in situ or in a separate step, and this intermediate undergoes clean enantioselective S(N)2' substitution with a variety of carboxylic acids in the presence of the palladium(II) catalyst (R(p),S)-di-μ-acetatobis[(η(5)-2-(2'-(4'-methylethyl)oxazolinyl)cyclopentadienyl-1-C,3'-N)(η(4)-tetraphenylcyclobutadiene)cobalt]dipalladium, (R(p),S)-[COP-OAc](2), or its enantiomer. The scope and limitations of this useful catalytic asymmetric allylic esterification are defined.