Abstract
Nickel-catalyzed cross-coupling reactions are among the most powerful tools in organic synthesis owing to the low cost, natural abundance and high activity of versatile nickel catalysts. However, there is a scarcity of efficient Ni-catalyzed systems for the cross-coupling of bench-stable, readily accessible and orthogonal C-O electrophiles. Herein, we report the cross-coupling of aryl sulfamates enabled by sterically-demanding and electron-rich N-heterocyclic carbenes. The study identified sulfamates as the most reactive C-O electrophiles enabled by a combination of IPr*(OMe) bearing sterically-demanding ortho-diphenyl wingtip substitution and NiF(2) exploiting the fluoride effect. The system enables efficient C(sp(2))-C(sp(2)) and C(sp(2))-C(sp(3)) cross-coupling avoiding hydrolysis, homocoupling and unselective C-O and S-N cleavages, providing a powerful platform for the orthogonal use of C-O electrophiles. The system is also applicable to Buchwald-Hartwig amination. The broad access to electron-rich, sterically-demanding N-heterocyclic carbenes combined with the high reactivity of aryl sulfamates furnishes a commanding avenue for the development of Ni-catalyzed processes in academic and industrial research.