Organoboranes

The exchange and substitution reactions of 9-borabicyclo[3.3.1]nonane (9-BBN) and its B-substituted derivatives with various reagents have been studied. The reaction of 9-BBN with halogens and hydrogen halides provides a simple route to B-halo-9-BBN's (B-X-9-BBN, X = Cl, Br, I). These B-X-9BBN's can also be prepared by the facile redistribution reaction between the respective boron trihalides and 9-BBN or B-OMe-9-BBN. The alcoholysis of 9-BBN or B-X-9-BBN affords B-alkoxy-9-BBN in high yield. The exchange reaction between B-alkoxy-9-BBN and borane-methyl sulfide affords 9-BBN in quantitative yield. This study reports the simple procedures for the interconversion of a variety of B-substituted 9-BBN's.