Ligandless Copper‐Catalyzed Carboborylation of Heteroatom‐Substituted Alkynes

Abstract

We have developed an efficient ligandfree copper-catalyzed regio-and stereoselective carbo-borylation of heteroatom-substituted internal alkynes using bis(pinacolato)diboron as boron source and alkyl halides as an electrophile. Both chemical yields and functional group tolerance are excellent. Our method provides an efficient synthesis of tri-and tetra-substituted alkenylboronates which could be further transformed to highly substituted alkenes via subsequent cross-coupling reactions in one pot.

Copper-Catalyzed Borylative Difunctionalization of π-Systems

“…Furthermore, derivatizations of the vinylboronate products demonstrated their versatility toward new C–C, C–O, and C–X bonds. Recent investigations by the Xu lab have expanded the range of alkynes that participate in the borylalkylation process to include thioalkynes, ynamides, and ynol ethers …”

Encapsulation of Cu2O Micro/Nanoparticles into Activated Carbon Felt as a Catalyst in Organic Reactions

“…Alkenylboronates are synthetically versatile building blocks whose carbon–boron bonds can be transformed into carbon–carbon , or carbon–heteroatom bonds to give valuable multisubstituted alkenes. Among various synthesis methods, copper-catalyzed borylation of alkynes to access alkenylboronates is one of the most effective approaches. , However, this protocol usually cannot offer ideal regioselectivity in the absence of ligands . However, the catalysts used in this reaction commonly cannot be recycled by filters due to homogeneous reactions.…”

“…Among various synthesis methods, copper-catalyzed borylation of alkynes to access alkenylboronates is one of the most effective approaches. 40,41 However, this protocol usually cannot offer ideal regioselectivity in the absence of ligands. 42 However, the catalysts used in this reaction commonly cannot be recycled by filters due to homogeneous reactions.…”

Copper‐Catalyzed Preparation of Alkenylboronates and Arylboronates

“…In presence of CuCl and K 3 PO 4 , reactions of a variety of thioalkynes, ynamides and ynol ethers with B 2 pin 2 and alkyl halides resulted in the formation of heteroatomsubstituted (Z)-β-alkenylboronates selectively (Scheme 24b). [144] Copper-catalyzed heteroboration involving the addition of tive for Cu-Bpin mediated borylstannylation (Scheme 25a). [145] The Xu Group have reported a copper-catalyzed regiodivergent cis-silaboration of different terminal alkylacetylenes to prepare both the two regioisomeric silyl bearing alkenylboronates selectively by tuning the Cu-sources (CuTC, copper isocaprylate) and P-ligands (PCy 3 , PPh t Bu 2 : L41) (Scheme 25b).…”