Chan-Lam Amination of Secondary and Tertiary Benzylic Boronic Esters

We report a Chan-Lam coupling reaction of benzylic and allylic boronic esters with primary and secondary anilines to form valuable alkyl amine products. Both secondary and tertiary boronic esters can be used as coupling partners, with mono-alkylation of the aniline occurring selectively. This is a rare example of a transition-metal-mediated transformation of a tertiary alkylboron reagent. Initial investigation into the reaction mechanism suggests that transmetalation from B to Cu occurs through a single-electron, rather than a two-electron process.

Automated summary

In this study, a Chan-Lam coupling reaction of benzylic and allylic boronic esters with primary and secondary anilines was reported to form valuable alkyl amine products. Both secondary and tertiary boronic esters were used as coupling partners, resulting in selective mono-alkylation of the aniline. This rare example demonstrated a transition-metal-mediated transformation of a tertiary alkylboron reagent, with initial investigation suggesting a single-electron transmetalation mechanism from B to Cu.