Practical Synthesis of Chiral Allylboronates by Asymmetric 1,1-Difunctionalization of Terminal Alkenes

We report herein a modular catalytic method for the efficient enantioselective synthesis of chiral allylboronates from abundant feedstock chemicals through an asymmetric 1,1-difunctionalization of alkenes. This protocol is distinguished by its use of an inexpensive chiral catalyst, mild and convenient reaction conditions, wide substrate scope, scalability and practicality. The utility of this method is demonstrated by the rapid synthesis of key intermediates of complex drug molecules. Mechanistic studies reveal that beta-H elimination is a highly regioselective step and the reversible homolysis and convergance to the lower energy pre-reductive elimination intermediate is the enantio-determining step.

Automated summary

We report a modular catalytic method for the enantioselective synthesis of chiral allylboronates from abundant feedstock chemicals. This method shows advantages in terms of the use of inexpensive catalyst, mild reaction conditions, wide substrate scope, scalability, and practicality. The utility of the method is demonstrated by the rapid synthesis of key intermediates of complex drug molecules. Mechanistic studies reveal the regioselective nature of beta-H elimination and the enantio-determining step involving reversible homolysis and convergance to a lower energy pre-reductive elimination intermediate.