[75030-54-5]  · C6H14BCl  · Chloro(thexyl)borane  · (MW 132.43)

(hydroboration agent)

Alternate Name: chloro(1,1,2-trimethylpropyl)borane.

This reagent, which was first used in hydroboration reactions by Zweifel and Pearson,1 has been replaced by Chloro(thexyl)borane-Dimethyl Sulfide. In fact, Zweifel and Pearson prepared their reagent from borane-dimethyl sulfide in THF, so there is reason to believe that they were actually working with the dimethyl sulfide complex of the chloro(thexyl)borane that they prepared. Brown and Sikorski2 have prepared chloro(thexyl)borane free of dimethyl sulfide in both THF and Et2O and examined the reactions of the reagents obtained with alkenes in the same solvents. The THF complex of chloro(thexyl)borane could be obtained cleanly by treating BH2Cl with 2,3-dimethyl-2-butene in THF, but the same reaction in Et2O gave a complex, equilibrating mixture containing thexylborane, chloro(thexyl)borane, and dichloro(thexyl)borane. Hydroboration of terminal alkenes with the chloro(thexyl)borane reagent in THF (or with the complex mixture obtained in Et2O) led to mixtures containing trialkylborane, dialkylchloroborane, and alkyldichloroborane species. However, these workers showed that the chloro(thexyl)borane-dimethyl sulfide reagent in CH2Cl2 reacts cleanly with alkenes to give the desired alkylchlorothexylborane product.2

1. Zweifel, G.; Pearson, N. R. JACS 1980, 102, 5919.
2. Brown, H. C.; Sikorski, J. A. OM 1982, 1, 28.

William S. Mungall

Hope College, Holland, MI, USA

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