Cycloaddition and chlorotropic transformations in reactions of dichloromethylenetrifluoroacetamide with phosphites

Reactions of dichlormethylenetrifluoroacetamide with triphenyl phosphite, diethylchlorophosphite (o-phenylene)diethylamidophosphite, (o-phenylene)chlorphosphite, and 2-fluoro-3-isopropyl-5-tert-butyl-1,3,2-oxazaphospholine proceeded as cheletropic 4+1]-cycloaddition. The formed λ⁵-1,4,2-oxazaphospholines underwent 1,3-migration of the chlorine atom in C=N–C cyclic triad.