Dilongifolylborane

Dilongifolylborane is a reagent for asymmetric hydroboration of prochiral alkenes.

Dilongifolylborane is readily prepared by hydroboration of (+)-longifolene with Borane-Dimethyl Sulfide (BH3.SMe2) in a 2:1 ratio (eq 1).

Wash it with dry Et2O and dry it in a vacuum under N2. It has m 160-161o in a sealed evacuated capillary. It is sparingly soluble in pentane, tetrahydrofuran, carbon tetrachloride, dichloromethane, and chloroform, but the suspended material is capable of causing asymmetric hydroboration. Disappearance of solid indicates that the reaction has proceeded. [Jadhav & Brown J Org Chem 46 2988 1981.]

Guidelines for handling air- and moisture-sensitive reagents should be followed. The pure reagent is described as an irritant.