Copper-Catalyzed Regio- and Stereoselective Intermolecular Three-Component Oxyarylation of Allenes

Abstract

A copper(II)-catalyzed intermolecular three-component oxyarylation of allenes using arylboronic acids as a carbon source and TEMPO as an oxygen source is described. The reaction proceeded under mild conditions with high regio- and stereoselectivity and functional group tolerance. A plausible reaction mechanism is proposed, involving carbocupration of allenes, homolysis of the intervening allylcopper(II), and a radical TEMPO trap.

Cu-catalyzed C–C bond formation of vinylidene cyclopropanes with carbon nucleophiles

“…[4][5][6][7] However, few methods are currently available allowing for catalytic reactions of Cu-based carbon nucleophiles with allenes. 8 We developed and report herein our studies on Cu-catalyzed reactions of vinylidene cyclopropanes with carbon nucleophiles generated from 1,1-bisborylmethane and alkynyl boronates to deliver synthetically useful homopropargylic boronate and skipped diyne products.…”

Copper-mediated arylation with arylboronic acids: Facile and modular synthesis of triarylmethanes

“…Based on the above observations, we propose a mechanism for the copper-mediated coupling of phenylboronic acid with diphenylmethanol, leading to triphenylmethane and boric acid ( Scheme 3 ). At the start of the cascade, the first step is the transmetallation of the copper(II) into phenylboronic acid to form reactive PhCu(OTf) ( 15 ) and B(OH) 2 (OTf) [ 61 ]. The intermediate 15 then reacts with diphenylmethanol 9 to provide the intermediate 16 .…”

Enantioselective copper catalysed, direct functionalisation of allenes via allyl copper intermediates

“…Finally, Shimizu and Kanai reported that allenes 73 undergo oxyarylation in the presence of a variety of aryl boronic acids 74 and TEMPO to yield β-arylated allylic alcohol derivatives 75 under copper catalysis ( Scheme 13 ). 35 Copper( i ) salts were also effective in the transformation but Cu(OTf) 2 was optimal. The mechanism is proposed to go through initial transmetallation of copper with aryl boronic acids to form aryl copper 76 ( Scheme 13B ).…”