79200-86-5Relevant articles and documents
Organoboranes. 26. 11B NMR investigation of reactions of 2,3-dimethyl-2-butene with monochloroborane complexes. Preparation and hydroboration characteristics of thexylchloroborane reagents
Brown, Herbert C.,Sikorski, James A.
, p. 28 - 37 (2008/10/08)
Under selected conditions, the hydroboration of 2,3-dimethyl-2-butene with 1 equiv of monochloroborane proceeds cleanly to give the monohydroboration product, thexylchloroborane (ThxBHCl). This reaction was examined with several monochloroborane complexes, including BH2C1·THF, BH2Cl·OEt2, and BH2Cl·SMe2. The resulting thexylchloroboranes were fully characterized by IR and 11B NMR spectroscopy. Monomeric ThxBHCl·THF was obtained cleanly from BH2C1middot;THF. Similarly, monomeric ThxBHCl·SMe2 was obtained cleanly from BH2Cl·SMe2. On the other hand, the product resulting from hydroboration of 2,3-dimethyl-2-butene with BH2Cl·OEt2 was demonstrated to be a complex, equilibrating mixture of thexylborane (dimeric), thexylchloroborane, and thexyldichloroborane. The hydroboration properties of each of these reagents were also examined. Hydroboration of terminal alkenes with the ThxBHCl·THF and ThxBHCl/Et2O reagents led to complex mixtures containing trialkylborane, dialkylchloroborane, and alkyldichloroborane species. However, hydroboration of terminal alkenes with ThxBHCl·SMe2 in CH2Cl2 proceeded cleanly to the desired dialkylchloroborane product. Subsequent oxidation produced the desired primary alcohols in nearly quantitative yields with high regioselectivity.