Computational studies of ring cleavage and deoxygenation reactions of a σ3λ3-oxaphosphirane

Abstract

The thermal stability of a σ³λ³-oxaphosphirane is computationally explored with regard to their ring-opening reactions. The possibility of deoxygenation by trivalent phosphorus reagents, leading to phosphaalkenes, is found to be disfavoured by direct attack of P to O but, instead, the initial C-attack is kinetically preferred leading to a 1,2,4-oxadiphosphetane via the corresponding betaine. Epimerization of this four-membered ring, from the initial erythro to the most stable threo diastereomeric pair, enables [2+2] cycloreversion to the most stable final E-phosphaalkene as the final deoxygenation product.