Direct regio- and diastereoselective diphosphonylation of cyclic enamines : one-pot synthesis of α,α′-bis(diphenylphosphoryl)- and α,α′-bis(diphenylphosphorothioyl)cycloalkanones

A straightforward regio- and diastereoselective process has been developed for the synthesis of unprecedented symmetrical trans-alpha,alpha '-bis(diphenylphosphoryl)- and alpha,alpha '-bis(diphenylphosphorothioyl)cycloalkanones, through the reaction of cyclic enamines with excess P-chlorodiphenylphosphine in the presence of triethylamine, followed by oxidation or sulfurization and hydrolytic workup