Pd(ii)-catalyzed cyclization of alkyne-tethered malononitriles via nitrile insertion

Abstract

Herein, we have developed a Pd(II)-catalyzed cyclization of prochiral alkyne-tethered malononitriles to access five-membered carbocycles having a nitrile-containing all-carbon quaternary center. The reaction pathway involves a trans-acetoxypalladation, nitrile group insertions into the carbon-palladium bond and sequential deacetylation followed by N-acetylation. Initial studies on asymmetric cyclization were also performed with chiral Pyox ligands.