Asymmetric synthesis of α-substituted alkylphosphonates based on symmetrical dialkyl phosphites

Chiral C-2-symmetrical dialkyl phosphites and C-3-symmetrical trialkyl phosphites, derived from (-)-borneol, (-)-menthol, and 1,2:5,6-di-O-isopropylidene-alpha-D-glucofuranose, were studied as the starting reagents for the preparation of chiral organophosphorus compounds. The reactions of C-2-symmetrical dialkyl phosphites and C-3-symmetrical trialkyl phosphites with aldehydes and amines or aldehydes are accompanied by asymmetrical induction at the alpha-carbon atom to yield optically active alpha-aminoalkylphosphonates or alpha-hydroxyalkylphosphonates, respectively. The stereoselectivity of the reaction depends on the structure of the starting compounds and the reaction conditions.