SYNTHESIS OF TRICYCLIC (LAMBDA(5))-PHOSPHORANES - UNUSUAL N-DEMETHYLATION N-ALKYLATION REACTIONS DURING THE OXIDATIVE ADDITION OF HEXAFLUOROACETONE AND TETRACHLORO-ORTHO-BENZOQUINONE TO BENZODIAZA-LAMBDA(3)-PHOSPHORINONES - SINGLE-CRYSTAL X-RAY-DIFFRACTION STUDIES OF VARIOUS PRODUCTS/

The reaction of methylisatoic acid anhydride 1 with benzylamines led t o the N-benzyl-N'-methylanthranilamide derivatives 2-4. Their reaction with phosphorus trichloride furnished the l-3-methyl-4(1H)-1,3,2-benz odiazaphosphorin-4-ones 5-7 which, upon reaction with bis-(2-chloroeth yl)ammonium chloride/triethylamine, were converted into the l-3-methyl -4(1H)-1,3,2-benzodiazaphosphorin-4-ones 8-10 and 12. With 2-chloroeth ylammonium chloride/triethylamine the P-NHCH2CH2Cl-substituted compoun d 11 was obtained from the (PCl)-Cl-III-species 6. The reaction of 8-1 0 and 12 with hexafluoroacetone (HFA) took an unusual course: apart fr om the oxidative addition of HFA and formation of the perfluoropinacol yl ring system, one of the two CH2CH2Cl groups was found to alkylate t he CH3N atom with formation of a five-membered (diazaphospholane) ring in the tricyclic phosphoranes 13-16. The reaction of 11 with HFA also produced a spirophosphorane 17 which involved a lambda 5-ox-azaphosph etidine ring system. In the reaction of 8, 10 and 12 with tetrachloro- o-benzoquinone, an oxidative addition reaction with concomitant N-alky lation and formation of the tricyclic phosphoranes 18-20 was found to take place. Single crystal X-ray structure determinations are describe d for the phosphoranes 13, 14 and 16, and for the precursor compound 9 . The following features are common to the isostructural compounds 13 and 16 and the diethyl ether hemisolvate of 14: the (lambda(5))-spiro phosphorus atom lies out of the plane of the other atoms of the rings to which it is common, and the dioxaphospholane rings display a twist conformation. In the lambda(3)P-compound 9 the phosphorus atom also li es out of the plane of the other ring atoms.