Construction of quaternary stereogenic carbon centers through copper-catalyzed enantioselective allylic cross-coupling with alkylboranes

Kentaro Hojoh; Yoshinori Shido; Hirohisa Ohmiya; Masaya Sawamura

doi:10.1002/anie.201402386

Construction of quaternary stereogenic carbon centers through copper-catalyzed enantioselective allylic cross-coupling with alkylboranes

Angew Chem Int Ed Engl. 2014 May 5;53(19):4954-8. doi: 10.1002/anie.201402386. Epub 2014 Mar 25.

Authors

Kentaro Hojoh¹, Yoshinori Shido, Hirohisa Ohmiya, Masaya Sawamura

Affiliation

¹ Department of Chemistry, Faculty of Science, Hokkaido University, Sapporo 060-0810 (Japan) http://wwwchem.sci.hokudai.ac.jp/∼orgmet/index.php.

PMID: 24668885
DOI: 10.1002/anie.201402386

Abstract

A combination of an in situ generated chiral Cu(I) /DTBM-MeO-BIPHEP catalyst system and EtOK enabled the enantioselective SN 2'-type allylic cross-coupling between alkylborane reagents and γ,γ-disubstituted primary allyl chlorides with enantiocontrol at a useful level. The reaction generates a stereogenic quaternary carbon center having three sp(3) -alkyl groups and a vinyl group. This protocol allowed the use of terminal alkenes as nucleophile precursors, thus representing a formal reductive allylic cross-coupling of terminal alkenes. A reaction pathway involving addition/elimination of a neutral alkylcopper(I) species with the allyl chloride substrate is proposed.

Keywords: allylic compunds; asymmetric catalysis; boron; copper; synthetic methods.