• Precursor of the sterically hindered hydroborating reagent, "thexylborane", introduced by Brown: J. Am. Chem. Soc., 94, 3561 (1972). For review of its chemistry, see: Synthesis, 77 (1974). This reagent should be freshly prepared since it rearranges on standing to 2,3-dimethyl-1-butylborane.