Synthesis of P, B-containing heterocycles based on bis(?,2-dihydroxybenzyl)phenylphosphine

Reaction of bis(α,2-dihydroxybenzyl)phenylphosphine and its derivatives with the isobutyl ester of diphenylboric acid, the anhydride of phenylboric acid, and boric acid in the presence of amines forms ammonium 2,8,9-trioxa-1-borata-4-phospha-6,7-benzobicyclo[3.3.1] non-6-enes. Reaction with 2 equivalents of the isobutyl ester of diphenylboric acid gives bis(triethylammonium 2,2-diphenyl-5,6-benzo-1,3,2-dioxaborin-4-yl)phenylphosphine oxide.