A useful sequence of reactions for the synthesis of a variety of heterocyclic systems is described. The reaction of benzoin-α-oxime (2-hydroxy-1,2-diphenyl-1-ethanone oxime) with sodium hydride in propan-2-ol produces a 1,5-dianion. The cyclization of this dianion with dielectrophiles affords dioxazines, dioxazepines, dioxazocine, dioxazonine and dioxazaphosphines in good yields.
electrophilic cyclizations - benzoin-α-oxime - dioxazines - dioxazepines - dioxazocine - dioxazonine - dioxazaphosphines
