Suzuki-Miyaura Coupling of (Hetero)Aryl Sulfones: Complementary Reactivity Enables Iterative Polyaryl Synthesis.

Ideal organic syntheses involve the rapid construction of C-C bonds, with minimal use of functional group interconversions. The Suzuki-Miyaura cross-coupling (SMC) is a powerful way to form biaryl linkages, but the relatively similar reactivity of electrophilic partners makes iterative syntheses involving more than two sequential coupling events difficult to achieve without additional manipulations. Here we introduce (hetero)aryl sulfones as electrophilic coupling partners for the SMC reaction, which display an intermediate reactivity between those of typical aryl (pseudo)halides and nitroarenes. The new complementary reactivity allows for rapid sequential cross-coupling of arenes bearing chloride, sulfone and nitro leaving groups, affording non-symmetric ter- and quateraryls in only 2 or 3 steps, respectively. The SMC reactivity of (hetero)aryl sulfones is demonstrated in over 30 examples. Mechanistic experiments and DFT calculations are consistent with oxidative addition into the sulfone C-S bond as the turnover-limiting step. The further development of electrophilic cross-coupling partners with complementary reactivity may open new possibilities for divergent iterative synthesis starting from small pools of polyfunctionalized arenes.