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

Herein, the use of economically and environmentally friendly bis(pinacolato)diboron (B 2 Pin 2 ) is described as a non-metallic reductant in mediating Ni-catalyzed C(sp 3 )-C(sp 2 ) 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 B 2 Pin 2 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 B 2 Pin 2 can sever as a reductant to reduce Ni II to Ni 0 . This mechanistic insight may inspire the development of new reductive bond-forming methodologies that can otherwise be difficult to achieve with a metal reductant.