Dimesitylaminoboranes and unsymetric triaminoboranes. Stability of aminodioxaboroles and dimesitylboroxyethanol

Bulky dimesitylaminoboranes, unsymetric triaminoboranes and an amino borons ulfonamide were prepared either by transmetallation or transamination react ions. From tris(diethylamino)borane, diethylaminodioxaborole was obtained e ither by protic cleavage by 3,5-di-t-butylcatechol or by addition reaction of 3,5-di-t-butyl-o-quinone through S.E.T. in the first step of the reactio n. From the same tris(diethylamino)borane, 1,2-ethanediol did not lead to t he expected diethylaminodioxaborolane but to 2,5,7,10, 11,14-hexaoxa-1,6-di borane bicyclo[4.4.4.]tetradecane. 2-dimesitylboroxyethanol, isolated as a white powder, is not thermally stable and leads either to 1,2-bis(dimesityl boroxy) ethane or to 1,3-dioxaborolane with mesitylene elimination. Dimesit ylboranes undergo nucleophilic substitution of a mesityl group in the prese nce of a strong nucleophile.