Parallel and Combinatorial Liquid-Phase Synthesis of Alkylbiphenyls Using Pentaerythritol Support

Abstract

Unfunctionalized alkylbiphenyls were fabricated by a parallel and combinatorial synthesis using pentaerythritol as a tetrapodal soluble support for a sulfonate-based traceless multifunctional linker system. Nickel N-heterocyclic carbenecatalyzed reactions of pentaerythritol tetrakis(biphenylsulfonate)s with primary alkylmagnesium bromides generated the allcylbiphenyl derivatives by desulfitative cleavage/cross-coupling of the C S bond without any "memory" of the attachment on the support. Though the reactions were completed with sufficient yields in 12 h at room temperature, even with only 1.5 equiv of nucleophiles, they still retained the benefits of facile isolation observed in polymer-supported reactions.