Nickel-Catalyzed Reductive Coupling of Unactivated Alkyl Bromides and Aliphatic Aldehydes

We report the development of a mild, convenient coupling of aliphatic aldehydes and unactivated alkyl bromides. The catalytic system features the use of a common Ni(II) precatalyst and a readily available bisoxazoline ligand and affords silyl-protected secondary alcohols. The reaction is operationally simple, utilizing Mn as a stoichiometric reductant, and tolerates a wide range of functional groups. Initial mechanistic experiments support a mechanism featuring an alpha-silyloxy Ni species which undergoes formal oxidative addition of the alkyl bromide species via a reductive cross-coupling pathway.