Nickel(II) Catalyzed Hydroboration: A Route to Selective Reduction of Aldehydes and N-Allylimines

Article abstract of DOI:10.1002/ejic.202000092

A cationic [(iminophosphine)nickel(allyl)]⁺ complex was found to be sufficiently electrophilic to activate aldehydes and N-allylimines to undergo hydroboration with pinacolborane (HBpin) under mild reaction conditions. The catalyst displayed excellent selectivity toward aldehydes in the presence of ketones. A wide variety of functional groups were tolerated, including halogens, NO₂, CN, OMe, and alkenes for both aldehydes and imines. Electron-rich substrates were found to be significantly more reactive than their electron poor counterparts, a feature that was correlated to their enhanced ability to coordinate to the Lewis acidic nickel center.