Copper-Catalyzed Asymmetric Borylacylation of Styrene and Indene Derivatives

Abstract

The enantioselective copper-catalyzed borylacylation of aryl olefins with acyl chlorides and bis-(pinacolato)­diboron is reported. This three-component reaction involves an enantioselective syn-borylcupration of the aryl olefin, followed by a nucleophilic attack on the acyl chloride. This reaction proceeds with a 2 mol % catalyst loading and is generally completed within 30 min at room temperature. Because the boron moiety can be converted into versatile functional groups and the carbonyl group is a ubiquitous functional group, the resulting chiral β-borylated ketones are versatile intermediates in organic synthesis.

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

“…Using CuCl­(SIMes) as the catalyst and LiO t Bu as the base, internal alkynes react to afford carboxamides bearing vinylboronates in good yields. Borylacylation of styrene and indene derivatives with acylchlorides can also be carried out in the presence of copper and B 2 pin 2 . Most recently, Wu and co-workers reported the synthesis of stereodefined cyclopropyl bis­(boronates) from terminal alkenes with carbon monoxide.…”

“…Borylacylation of styrene and indene derivatives with acylchlorides can also be carried out in the presence of copper and B 2 pin 2 . 600 Most recently, Wu and coworkers reported the synthesis of stereodefined cyclopropyl bis(boronates) from terminal alkenes with carbon monoxide. The ideal conditions were identified as CuCl(IPr) as the copper precatalyst in the presence of Xantphos as the ligand and NaOEt as the base in dimethylacetamide (DMAc).…”

Copper‐Catalyzed Regio‐ and Diastereoselective Borylacylation ofα,β‐Unsaturated Esters

“…In 2017, Brown reported pioneering work on the copper‐catalyzed borylacylation of styrenes, 1,3‐dienes, and strained alkenes with B 2 pin 2 and acyl chlorides [6a] . Since then, the borylacylation of versatile π‐systems such as allenes, imines, and enynes has been developed by many research groups [6b–i] . Despite the aforementioned certain progress, there is no successful report on borylacylation of α, β ‐unsaturated carbonyl compounds [7] .…”

Copper catalyzed borocarbonylation of benzylidenecyclopropanes through selective proximal C–C bond cleavage: synthesis of γ-boryl-γ,δ-unsaturated carbonyl compounds

“…11 j However, to the best of our knowledge, the capture of the Cu–C bond from such β-carbon elimination of BCPs with a carbon electrophile other than a proton has been less reported. 12 Herein, we report a copper catalyzed borocarbonylation 13 of BCPs with B 2 pin 2 and chloroformates (or acyl chlorides) through the cleavage of a proximal C–C bond of the cyclopropane ring for the synthesis of γ-boryl-γ,δ-unsaturated carbonyl compounds ( Scheme 1c ). 14 Notable features of our study include: (1) regio- and stereoselective boroacylation of BCPs through selective proximal C–C bond cleavage, (2) preparation of 1,3-difunctionalized products with γ-boryl-γ,δ-unsaturated carbonyl compounds, and (3) broad substrate scopes as well as good functional group tolerance.…”