Bulky Yet Flexible Pd-PEPPSI-IPentAn for the Synthesis of Sterically Hindered Biaryls in Air.

In this report, a type of moisture and air stable Pd-PEPPSI-IPentAn complex (C1) with the combination of acenaphthyl on the backbone and isopentyl groups on N-aryl moieties was described and applied in the Suzuki-Miyaura cross-coupling reaction in air. The reaction conditions were optimized, and the structure-reactivity relationships between C1 and other classical efficient Pd-PEPPSI complexes were investigated intensively. Our study demonstrated that both the backbone and N-aryl moieties gave rise to a significant effect on this transformation when exposed to air. A wide range of sterically hindered (hetero)aryl chlorides with (hetero)arylboronic acids were compatible, giving good to excellent isolated yields of sterically hindered bi(hetero)aryls.