Regiodivergent and Enantioselective Hydroboration of Dienol Ethers

Abstract

Abstract Transition metal‐catalyzed asymmetric hydroboration of alkenes is one of the most straightforward methods for the synthesis of chiral organoboron compounds and has been well‐established. While significant progress has been made in the catalytic enantioselective hydroboration of simple dienes, the development of regiodivergent and enantioselective hydroboration of more challenging substrates such as heteroatom‐substituted or trisubstituted dienes remains limited. Here, we disclose a cobalt‐catalyzed regiodivergent and enantioselective hydroboration of dienol ethers using a commercially available Co(acac) 2 catalyst and chiral ligands. The reaction exhibits good functional group compatibility and broad substrate scope, selectively affording 1,2‐, 4,1‐, 1,4‐, and 4,3‐hydroboration products in good yields and high regio‐ and enantioselectivities (up to >99%). Mechanistic studies, including deuterium‐labeling, kinetic, and UV–vis experiments, suggest the involvement of Co–H species as active catalysts in the reactions. The powerful conversion capabilities of the products are demonstrated by various downstream transformations and the efficient preparation and late‐stage elaboration of bioactive compounds.