text: Treatment of diisopinocampheylborane with TMEDA give the crystalline adduct of monoisopinocampheylborane.  This adduct reacts with boron trifluoride to liberate the monoisopinocampheylborane (IpcBH) in 100% ee. Monoisopinocampheylborane reacts with a variety of alkenes.  Two other reagents have been developed for the hydroboration of ketones:
  In the above mechanism where G=O and R is Ipc and Cl or 9-Borabicyclononane.  Diisopinocampheylchloroborane (IpcBCl) is produced by treating diisopinocampheylborane with hydrogen chloride. The chloride is reported to be more stable that the trialkyl boranes, it works well with aryl alkyl ketones and tert-butyl alkyl ketones. Diisopinocampheylchloroborane is often complementary with diisopinocampheylborane, where one provides the R enantiomer and the other the S, the enantioselectivity is typically very high.
  Alpine-borane is produced by hydroborating α-pinene with 9-borabicyclononane. Both of these reagents can be improved upon by using 2-ethylapopinene in place of α-pinene, 2-ethylapopinene has an ethyl group in place of the methyl in α-pinene. The additional steric bulk improves the stereoselectivity of the reduction.
  Diisopinocampheylborane reacts with methanol to give diisopinocampheylmethoxyborane, which in turn reacts with an allyl or crotyl Grignard reagent to give B-allyldiisopinocampheylborane. This can then undergo an asymmetric allylboration to give a chiral homologated alcohol, which is a useful building block in a chiral synthesis.