Trichloropyruvate N-acylimines. Reactions with phosphorus nucleophiles

Reactions of N-aroyltrichloroethaneimines CCl3C(R)=NCOAr (II, R = COOMe, CN) with phosphorus nucleophiles were studied. The reaction of imines II with o-phenylenediethylamidophosphite proceeded as [4+1]-cycloaddition leading to formation of stable spirocyclic phosphoranes. The structure of one of them was proved by the XRD analysis. The reaction of imine II with acyclic P(III) derivatives [Ph3P, Ph2POEt, (PhO)3P] also includes the formation of labile monocyclic phosphoranes which eliminate phosphine oxide and undergo chlorotropic transfer leading to trichloroazadienes CCl2=C(R)N=C(Cl)Ar. The reaction of imines II with (EtO)2POH in the presence of triethylamine leads to the formation of (EtO)2P(O)Cl and the corresponding dichlorovinylamides CCl2=C(R)NHCOAr.