Sereoselective Addition of Benzaldehyde N,N-Dimethyl-Hydrazone to 2-R_fO-4-Oxo-5,6-Benzo-1,3,2-Dioxaphosphorinanes. The Spatial Structure of 2-Pentafluorophenoxy-4-Dimethylamino-2,5-Dioxo-3-Phenyl-6,7-Benzo-1,4,2-Oxazaphosphepine

Abstract

[3+2]-Cycloaddition of N,N-dimethylhydrazone benzaldehyde (I) to 2-R_FO-4-oxo-5,6-benzo-l,3,2-dioxaphosphorinanes (II) yields the new heterocycle - 2-R_FO-4-Me₂N-2,5-dioxo-3-phenyl-6,7-benzo- 1,4,2-dioxaphosphepine (III) [R_F = C₆F₅, CH(CF₃)₂) with high stereoselectivity (above 94%). The reaction is likely to involve the initial interaction of nitrogen as a nucleophile with wbonyl carbon as an electrophile. The hydrolysis of (III) leads to phosphonic acid (IV) (OR_F = OH).