Zinc-Catalyzed Cross-Coupling of Triflates with Grignard Reagents

Abstract

A number of examples exist for the cross-coupling of sp³-centered electrophiles and nucleophiles, most notably the work of Fischer and Fu (J. Am. Chem. Soc. 2005, 127, 4594) using racemic secondary alkyl halides cross-coupled with organozinc regents, and Malosh and Ready employing a copper catalyst to cross-couple organozinc reagents with α-chloroketones (J. Am. Chem. Soc. 2004, 126, 10240). Alternately, starting from chiral substrates with stereo-retained control, addition of Grignard reagents has also been employed previously using stoichiometric amounts of transition-metal salts and cuprate reagents. This report utilizes a catalytic amount of zinc to perform this transformation with complete retention of stereoinformation.