The first catalytic method for the selective 1,4-conjugate allylation of α,β-unsaturated aldehydes is reported. The method employs an air-stable diethanolamine-complexed boronic acid (DABO boronate) as the allyl transfer reagent and promotes conjugate addition over 1,2-addition. A variety of aryl- and alkyl-substituted enals are tolerated, providing δ,ε-unsaturated aldehyde products in good yields and selectivities under mild conditions.

The scalable method represents the first catalytic procedure for the 1,4 over 1,2‐selective conjugate allylation of aryl as well as alkyl substituted α,β‐unsaturated aldehydes.