科研之友
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摘要
A synthetic method towards chiral benzimidazolium salts is developed. The stereocenter is introduced by direct aromatic substitution of 2-fluoronitrobenzene with optically pure amines. After nitro group reduction, selective arylation of the primary amine is achieved via copper catalyzed Chan-Lam coupling reaction. Finally, cyclization of the diamine with HC(OMe)(3) afforded the desired chiral benzimidazolium salts. In situ generated benzimidazole carbenes show potential application for asymmetric catalytic borylation of alpha,beta-unsaturated esters, providing up to 85% ee value with a catalyst loading of only 0.5 mol%.
- 出版日期2016-5-1
- 单位上海工程技术大学
