Diastereoselective Synthesis of Bulky, Strongly Nucleophilic, and Configurationally Stable P-Stereogenic Tricyclic Phosphines

A very simple, one-step highly diastereoselective synthesis of bulky, configurationally and air-stable P-chiral tricyclic phosphines 3, showing an exceptionally strong nucleophilic character, has been developed. This method involves the reaction of the stable phosphonium sila-ylide 1 with aryl- and alkyl-substituted acetylene derivatives. Starting from commercially available chiral (R,S)-(+)-endo-2-norborneol, the corresponding enantiomerically pure phosphines were obtained with excellent enantioselectivities (ee >= 99%) and high chemical yields.