Transition-metal-free C(sp3)–C(sp2) couplings with secondary alcohols and boronic acids via neighboring group activation†

ortho-Alkylated phenols are widely found in natural products and bioactive compounds. Here we have developed a mild, transition-metal-free approach for the C(sp³)–C(sp²) cross-coupling of alkenyl boronic acids with secondary alcohols via neighboring group activation, furnishing a series of ortho-allylphenols. The C(sp³)–hydroxyl group was activated through intramolecular interactions with ortho-phenolic functional groups (triflyl, tert-butoxycarbonyl, phosphoryl, and cyclic carbonate). This method exhibits good substrate compatibility, allowing for the efficient synthesis of ortho-allyl phenols and their subsequent transformation into high-value scaffolds.