Copper-Catalyzed Asymmetric Hydroboration of 2H-Chromenes Using a Chiral Diphosphine Ligand

Abstract

A highly regioselective asymmetric hydroboration of 2H-chromenes catalyzed by the complex of CuCl and diphosphine ligand (S,R)-DuanPhos has been realized under mild conditions to produce 3-boryl chromans, achieving good yields and excellent enantioselectivities up to 96% ee. This work provides an efficient approach to the synthesis of chiral 3-boryl chromans and derivatives.

First-Row d-Block Element-Catalyzed Carbon–Boron Bond Formation and Related Processes

“…In work reported by Hou, an enantioselective protoboration protocol led to chiral chromans (Scheme a) . Likewise, cyclopropyl boronate esters, which are important building blocks in medicinal chemistry, can be accessed with the appropriate choice of phosphine ligand.…”

“…548 In work reported by Hou, an enantioselective protoboration protocol led to chiral chromans (Scheme 147a). 549 Likewise, cyclopropyl boronate esters, which are important building blocks in medicinal chemistry, can be accessed with the appropriate choice of phosphine ligand. For example, protoboration of benzylidine cyclopropanes furnishes either cyclopropylboronate esters or alkenylboronates via suppression or promotion of cyclopropane opening, respectively.…”

Asymmetric synthesis of chiral (thio)chromanes and exploration on their structure–activity relationship in macrophages

“…The transition-metal catalyzed enantioselective functionalization of the C]C bond in 2H-chromene has been proved to be a direct and effective method for obtaining chiral chromanes. For instance, Hoveyda, 24 Hou, 25 and our group 26 realized copper (Cu)-catalyzed asymmetric hydroboration of 2H-chromenes in 2009, 2019 and 2022, respectively. In 2020 and 2021, our group 27,28 reported copper (Cu)-catalyzed asymmetric hydroamination of 2H-chromenes with N,N-dibenzylhydroxylamine ester (Fig.…”