Nickel-Catalyzed Enantioselective Synthesis of Cyclobutenes via [2+2] Cycloaddition of alpha,beta-Unsaturated Carbonyls with 1,3-Enynes

作者：Kumar Ravindra; Tamai Eri; Ohnishi Akira; Nishimura Akira; Hoshimoto Yoichi; Ohashi Masato; Ogoshi Sensuke

来源：Synthesis (Germany), 2016, 48(17): 2789-2794.

DOI：10.1055/s-0035-1561669

• nickel catalysis
• N-heterocyclic carbenes
• enantioselective
• intermolecular
• [2+2] cycloaddition
• cyclobutenes

A Ni(0)/chiral N-heterocyclic carbene (NHC) catalyzed enantioselective and intermolecular [2+2] cycloaddition of alpha,beta-unsaturated carbonyl compounds with conjugated enynes was investigated to produce enantioenriched cyclobutenes (up to 89% ee). The present report reveals the first example of a nickel-catalyzed enantioselective [2+2]-cycloaddition reaction. A newly synthesized imidazolinium salt, L*12 center dot HBF4, was the most effective NHC precursor for the present catalytic reactions.

• 出版日期2016-9