Rhodium‐Catalyzed Asymmetric Allylation of Malononitriles as Masked Acyl Cyanide with Allenes: Efficient Access to β,γ‐Unsaturated Carbonyls

A rhodium‐catalyzed regio‐ and enantioselective intermolecular allylation of malononitriles as masked acyl cyanides (MAC) with terminal and symmetrical internal allenes is reported. A Rh I /Josiphos catalytic system combined with subsequent oxidative degradation of the primary adducts enables a straightforward access to α‐branched, β,γ‐unsaturated carbonyl compounds. The present protocol exhibits perfect atom economy in the allylation step and is characterized by a great functional group compatibility. Furthermore, the use of α‐substituted malononitriles allowed for the construction of all‐carbon quaternary centers.