Copper(II)Chloride-Mediated Cyclization Reaction of N-Alkoxy-ortho-alkynylbenzamides

Abstract

A regioselective intramolecular cyclization/halogenation reaction of N-alkoxy-o-alkynylbenzamides with CuCl(2)/NCS was developed. The corresponding 3-(chloromethylene)isobenzofuran-1-ones were exclusively obtained via 5-exo-dig cyclization in moderate to excellent yields within 0.5-1 h. This approach has been successfully used to synthesize a biaryl compound by the Suzuki-Miyaura reaction.

Synergistic Effect of Palladium and Copper Catalysts: Catalytic Cyclizative Dimerization of ortho‐(1‐Alkynyl)benzamides Leading to Axially Chiral 1,3‐Butadienes

“…In fact, under the optimized conditions, the amide oxygen instead of the amide nitrogen was implicated in the 5-exodig cyclization leading to iminobenzoisofuran subunit at the expense of the isoindolinone and iminoisocoumarin. This cyclization mode has been rarely reported with o-(1-alkynyl)benzamides [16] and only few alternative methods existed in the literature for the synthesis of iminobenzoisofuran. [17] With optimum conditions in hand, the scope of this cyclizative dimerization was evaluated (Table 2).…”

Bioorthogonal release of anticancer drugs via gold-triggered 2-alkynylbenzamide cyclization

“…This rationale would be consistent with a similar report that showed the presence of a Weinreb amide can increase rates of N-alkoxy-2-alkynylbenzamide cyclization via copper catalysis. 53 To address the poor catalytic activity, it may be hypothesized that hydrolysis is a limiting factor under a Yields determined by HPLC (peak retention times compared to product standards, followed by MS analysis for conrmation, and then calculation of yields based on product standard curves). All reactions were standardized to 30 nmol of 3a,m and 30 nmol of catalyst in 50 ml of solvent (600 mM).…”

Radical Addition-Initiated Domino Reactions of Conjugated Oxime Ethers

“…As part of our ongoing research on the development of novel domino reactions, [3][4][5][6][7][8][9] we have recently focused our attention on the radical reactions of conjugated imines. Conjugated imines can be used as versatile building blocks for the efficient construction of nitrogen-containing heterocycles, as well as amino acids and amines, because they contain several reactive sites.…”