Efficient Synthesis of 2,8-Diphosphatricyclo[5.3.1.12,6]dodeca-3,5,9-triene 2,8-Dioxides.

The reaction of 1,2-dihydrophosphnine oxides (3a–3d) with tetracyanoethylene (TCNE) did not follow the Diels–Alder protocol, rather the corresponding diphosphatricyclododecatrienes (4a–4d) were formed in good yields. Interaction of the mesityl-dihydrophosphinine oxide (3f) with TCNE resulted in the formation of an α-dicyanomethylene derivative (5). [ABSTRACT FROM AUTHOR]