Direct Synthesis of Multi(boronate) Esters from Alkenes and Alkynes via Hydroboration and Boration Reactions

Multi(boronate) esters have been attracting increasing attention as versatile building blocks for the succinct and precise synthesis of complex molecules. However, there are a limited number of efficient synthetic procedures available. In this respect, the direct multiboration of alkenes and alkynes is undoubtedly an ideal route for their synthesis. During the past 30 years, catalytic systems based on transition-metals, organophosphines, bases, and even catalyst-free systems, with heat or with light irradiation for their straightforward preparation from alkenes and alkynes have been developed. Multi(boronate) esters with different numbers (up to 4) and positional relationships of the adjacent boron moieties were obtained, which are summarized and discussed herein.