Dearomative Allylation of Aromatic Cyanohydrins by Palladium Catalysis: Catalyst-Enhanced Site-Selectivity

A dearomative allylation of aromatic cyanohydrins with allyl borates and allyl stannanes under palladium catalysis was developed. At the initial stage of this study, the dearomative reaction (C4-substitution of the aromatics) was competing with benzyl substitution. To circumvent this issue, the use of palladium and meta-disubstituted triarylphosphine as the catalyst in a 1:1 ratio was found to enhance the site-selectivity, furnishing the desired dearomatized products. As the products possess an unsaturated nitrile moiety, further derivatizations of products such as conjugate additions and reductions were achieved.