Diboration of alkenes and alkynes with a carborane-fused four-membered boracycle bearing an electron-precise B-B bond.

Dalton Trans

Department of Chemistry and State Key Laboratory of Synthetic Chemistry, The Chinese University of Hong Kong, Shatin, N. T., Hong Kong, China.

Published: November 2021

Small ring compounds are fascinating molecules and have been used as valuable compounds in organic synthesis. In this study, a carborane-fused four-membered boracycle bearing an electron precise B-B bond, 1,2-[BBrSMe]--CBH, was synthesized the reaction of 1,2-Li--carborane with BBr(SMe). This novel boracycle can be used as a "strain-release" compound to achieve diboration of alkenes and alkynes, leading to the generation of ring-expansion products. Interestingly, when bis(trimethylsilyl) acetylene was employed, an allene-functionalized six-membered boracycle was obtained. Moreover, DFT calculations were conducted to shed light on the reaction mechanism.

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http://dx.doi.org/10.1039/d1dt03665cDOI Listing

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