Organophotoredox/Ni-Cocatalyzed Allylation of Allenes: Regio-, and Diastereoselective Access to Homoallylic Alcohols

A dual organophotoredox/nickel-catalyzed reductive coupling of allenes with aldehydes has been developed for the rapid assembly of anti-homoallylic alcohols with high levels of regioselectivities (>20:1), and diastereoselectivities (up to >20:1) and yields (up to 91%). The allylation was realized through a crucial π-allylnickel intermediate which was obtained via insertion of allenes with a Ni−H intermediate. Moreover, γ,γ-disubstituted homoallylic alcohols with a quaternary stereocenter can also be prepared by this protocol.