Bis(pinacolato)diboron-Enabled Ni-Catalyzed Reductive Arylation/Vinylation of Alkyl Electrophiles.

Herein, the use of economically and environmentally friendly bis(pinacolato)diboron (BPin) is described as a non-metallic reductant in mediating Ni-catalyzed C(sp)-C(sp) reductive cross-coupling of alkyl electrophiles with aryl/vinyl halides. This method exhibits excellent suitability for heteroaryl halides and alkyl halides/Katritzky salts. The present study is compatible with an in situ halogenation of alcohol method, allowing for selective mono-functionalization of diols and bio-relevant alcohols (e.g., carbohydrates). The use of BPin shows potential for easy scalability without introducing additional metal impurities into the products. It is observed for the first time in the realm of cross-electrophile coupling chemistry that BPin can sever as a reductant to reduce Ni to Ni. This mechanistic insight may inspire the development of new reductive bond-forming methodologies that can otherwise be difficult to achieve with a metal reductant.