MONOALKYLBORANE AND DIALKYLBORANE REAGENTS FROM SILYLAMINE-BORANES

New procedures for the simple, efficient preparation of thexylborane ( ThxBH(2)), disiamylborane (Siam(2)BH), 9-borabicyclo[3.3. 1]nonane (9- BBN-H) and diisopinocampheylborane (Ipc(2)BH) are described employing silylamine-boranes (1). By selecting a less reactive reagent, dicycloh exylborane (Chx(2)BH), was prepared directly from hydroboration in cry stalline form for the first time. These new methods demonstrate that t he silylamine by-products (2) neither interfere with subsequent reacti ons or purification of the borane reagents, nor pose any difficulties in their separation from the borane-derived products. (C) 1998 Elsevie r Science Ltd. All rights reserved.