Peculiar features of reaction of 2-tert-butoxy-5,6-benzo-1,3,2-dioxaphosphinin-4-one with chloral. Steric structure of 2-chloro-3-trichloromethyl-6,7-benzo-1,4,2λ ⁵-dioxaphopshepin-5-one 2-oxide

Abstract

The reaction of 2-tert-butoxy-5,6-benzo-1,3,2-dioxaphosphinin-4-one with chloral involves expansion of the six-membered heteroring to form 2-hydroxy-3-trichloromethyl-6,7-benzo-1,4,2λ ⁵-dioxaphosphepin-5-one 2-oxide as a single diastereomer. The product was chlorinated with thionyl chloride to obtain (RS,SR)-2-chloro-3-trichloromethyl-6,7-benzo-1,4,2λ ⁵-dioxaphosphepin-5-one 2-oxide.