Interrogating Pd(II) anion metathesis using a bifunctional chemical probe : a transmetalation switch

Molloy, John J. and Seath, Ciaran P. and West, Matthew J. and McLaughlin, Calum and Fazakerley, Neal J. and Kennedy, Alan R. and Nelson, David J. and Watson, Allan J. B. (2018) Interrogating Pd(II) anion metathesis using a bifunctional chemical probe : a transmetalation switch. Journal of the American Chemical Society, 140 (1). pp. 126-130. ISSN 0002-7863 (https://doi.org/10.1021/jacs.7b11180)

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Abstract

Ligand metathesis of Pd(II) complexes is mechanistically essential for cross-coupling. We present a study of halide→OH anion metathesis of (Ar)Pd(II) complexes using vinylBPin as a bifunctional chemical probe with Pd(II)-dependent cross-coupling pathways. We identify the variables that profoundly impact this event and allow control to be leveraged. This then allows control of cross-coupling pathways via promotion or inhibition of organoboron transmetalation, leading to either Suzuki-Miyaura or Mizoroki-Heck products. We show how this transmetalation switch can be used to synthetic gain in a cascade cross-coupling/Diels-Alder reaction, delivering borylated or non-borylated carbocycles, including steroid-like scaffolds.