Hydrophosphination of Bicyclo[1.1.0]butane-1-carbonitriles

Hydrophosphination of bicyclo[1.1.0]butyl nitriles with phosphine boranes and phosphites provided novel cyclobutyl-P derivatives. The reaction generally favors the syn-diastereomer, and the nitrile can be reduced and converted to other functional groups, thus enabling the preparation of bidentate ligands that access new conformational space by virtue of their attachment to the torsionally malleable but sterically restrictive cyclobutane scaffold. The enantioselective hydrogenation of dehydrophenylalanine using a bidentate phosphine-phosphite ligand illustrates the synthetic utility of the newly prepared scaffold.