Cu-catalyzed asymmetric borylative cyclization of cyclohexadienone-containing 1,6-enynes

J Am Chem Soc. 2013 Aug 14;135(32):11700-3. doi: 10.1021/ja404593c. Epub 2013 Jul 30.

Abstract

The first Cu-catalyzed asymmetric borylative cyclization of cyclohexadienone-containing 1,6-enynes is achieved through a tandem process: selective β-borylation of propargylic ether and subsequent conjugate addition to cyclohexadienone. The reaction proceeds with excellent regioselectivity and enantioselectivity to afford an optically pure cis-hydrobenzofuran framework bearing alkenylboronate and enone substructures. Furthermore, the resulting bicyclic products could be converted to bridged and tricyclic ring structures. This method extends the realm of Cu-catalyzed asymmetric tandem reactions using bis(pinacolato)diboron (B2pin2).