Organocatalytic <i>trans</i> Phosphinoboration of Internal Alkynes
Russell G. Fritzemeier, Jan Nekvinda, Christopher M. Vogels, Carol Ann Rosenblum, Carla Slebodnick, Stephen A. Westcott, Webster L. Santos
Abstract
Abstract We report the first trans phosphinoboration of internal alkynes. With an organophosphine catalyst, alkynoate esters and the phosphinoboronate Ph 2 P‐Bpin are efficiently converted into the corresponding trans ‐α‐phosphino‐β‐boryl acrylate products in moderate to good yield with high regio‐ and Z ‐selectivity. This reaction operates under mild conditions and demonstrates good atom economy, requiring only a modest excess of the phosphinoboronate. X‐ray crystallography experiments allowed structural assignment of the unprecedented and densely functionalized ( Z )‐α‐phosphino‐β‐boryl acrylate products.