Practical Solvent‐Free Microwave‐Assisted Hydroboration of Alkynes

A simple and rapid protocol for the anti-Markovnikov hydroboration of alkynes assisted by microwave irradiation has been developed. Pinacolborane smoothly reacts with terminal alkynes to obtain (E)-alkenyl boronates in good yields and short reactions times in the absence of solvent. Further transformations on the carbon-boron bond of the adducts can be sequentially achieved without the need of purifying the alkenyl boronates.