Diisopinocampheylborane is a hydroborane with many applications in organic synthesis of nicotine analogs, (-)-Invictolide, (+)-strictifolione and other organic compounds.
Diisopinocampheylborane is a chiral hydroboration reagent for asymmetric hydroboration of cis-alkenes to provide access to optically active secondary alcohols. It is a precursor for the preparation of a large number of chiral reagents for asymmetric synthesis.
(+)-diisopinocampheylborane is prepared in high enantiomeric purity and good yield (Table 1) by hydroboration of commercially available (-)-α-pinene (of low enantiomeric purity) with Borane-Dimethyl Sulfide (BMS) complex, carried out by mixing the two reagents to make a solution of known molarity in THF at 0 °C or rt (eq 1); the mixture is left without stirring at 0 °C for ~12 h for the development of crystals (the slow crystallization facilitates the incorporation of the major diastereomer in the crystalline product, leaving the undesired isomer in solution); the supernatant solution is decanted using a double-ended needle; the crystalline lumps are broken and washed with diethyl ether and dried under vacuum (~12 mmHg) at rt.
Diisopinocampheylborane is air sensitive, reacting instantaneously with protic solvents to liberate hydrogen; must be handled under an inert atmosphere (N2 or Ar); can be stored at 0 °C under inert atmosphere for several months without loss of hydride activity.
