Regioselective C(sp³) Carboboration of 1,3-Diynes: A Direct Route to Fully Substituted Enyne Boronates

Here, we report a general copper-catalyzed C(sp3) carboboration of 1,3-diynes, providing access to an array of tetra-substituted boryl enynes in a regioselective manner. All four positions of enyne can be efficiently manipulated using this methodology. The reaction was smoothly applied in the conjugation of complex bioactive molecules to the enyne scaffold. Cross-coupling reactions were carried out with boron end groups on densely substituted 1,3-enynes, opening avenues for the modular synthesis of highly functionalized enynes. Control experiments and density functional theory studies supported the proposed mechanism.