Synthesis and reactivity of new chiral bicyclic phospholanes as acyl-transfer catalysts

摘要

Synthesis of chiral phosphines 1a, 14a, and 18a as nucleophilic catalysts for anhydride activation and kinetic resolution of alcohols is described. Radical cyclization of alkenylphosphines produced the phosphabicyclooctane (PBO) core of catalysts la and 14a, while 18a was made by quenching a metallocycle precursor with dichlorophenylphosphine. Catalysts la and 14a are less reactive, while 18a is comparable to the most reactive catalysts in the PBO family. The preferred ground-state geometries of phosphine-boranes were identified using computational methods, and were correlated with the catalytic reactivity of the corresponding free phosphines.