Isopinocampheylbromoborane, a new promising reagent for the asymmetric hydroboration of prochiral alkenes

Article abstract of DOI:10.1016/S0040-4039(96)02118-1

A new promising in situ generated hydroborating agent, isopinocampheylbromoborane (IpcBHBr), achieves the asymmetric hydroboration of representative prochiral alkenes in pentane at lower temperatures, even at -78 °C, than has been possible with isopinocampheylborane (IpcBH₂) and isopinocampheylchloroborane·EE (IpcBHCl·EE) reagents, usually in higher enantioselectivities than previously achieved. This is first time that the asymmetric hydroboration of prochiral alkenes with an α-pinene-derived borane reagent (IpcBHBr) has been achieved at such low temperature, -78 °C, in a relatively short time, 4-6 h. Copyright (C) 1996 Elsevier Science Ltd.