An Overview of Ag‐catalyzed Synthesis of Six‐membered Heterocycles

Abstract

Heterocyclic chemistry is an immensely expanding field in organic synthesis owing to its potency in various disciplines like natural products chemistry, pharmaceuticals, drug discovery and industry. Silver catalysis has gained much attraction in recent years mainly in the scenario of heterocyclic synthesis. Among heterocycles, the six membered heterocycles are the most popular and widely applied in various fields. This review discusses on the investigations on various silver‐catalyzed synthesis of six‐membered heterocycles and covers literatures up to 2020.

Silver-catalyzed three-component reaction of uracils, arylboronic acids, and selenium: synthesis of 5-arylselanyluracils

“…Ag-catalyzed reactions are powerful tools for the formation of carbon–carbon and carbon–heteroatom bonds and are attracting increasing attention in modern organic chemistry. 17 Among these, Liu and co-workers developed Ag-catalyzed three-component reactions for C–Se bond formation using an arylboronic acid, Se powder, and an epoxide or acetylene derivative; 18–21 the reactions with epoxides catalyzed by AgNO 3 afford β-hydroxyselenides through epoxide ring-opening and selenation (Scheme 1a). 18 Reactions with 2-alkynyl-anisoles, -thioanisoles, -aryl esters, and alkynone O -methyloximes catalyzed by AgNO 3 and AgNO 2 gave furan and thiophene derivatives, isochromenones, and isoxazoles through the tandem cyclization and selenation (Scheme 1b and c).…”

Diastereoselective synthesis of tetrahydropyranes via Ag(i)-initiated dimerization of cinnamyl ethers

“…The method involves a sequential C(sp 3 )-O bond cleavage/C(sp 3 )-H bond functionalization, which is an original reactivity in the field of Ag-promoted processes. [17][18][19][20] As part of an ongoing interest on synthetic cascades, [21][22][23][24][25] we serendipitously observed the formation of macrocycle 2 in the presence of a Ru-based catalytic system originally developed by Sato and Mori 26 while treating diendiyne 1 with an Ag (I) salt. We soon realized that the Ag(I) salt used to trigger a putative chloride abstraction was actually the competent species for the conversion of 1 into 2.…”

“…The method involves a sequential C(sp 3 )–O bond cleavage/C(sp 3 )–H bond functionalization, which is an original reactivity in the field of Ag-promoted processes. 17–20…”

Editorial: Special Collection of Silver Catalysis in Organic Synthesis

“…[4] Another Review by Anilkumar exclusively summarized various methods for the synthesis of six-membered heterocyclic scaffolds using silver as a superlative catalyst. [5] The mechanism discussed in this review involves the initial coordination of silver to the substrate, followed by a 6-endo-dig cyclization, to give the products. A Minireview by Jiang, Wu and coworker provided insights on the silver-catalyzed reactions of electronically unbiased alkenes and alkynes, including the hydrofunctionalization, difunctionalization, cross-coupling and cyclization reactions.…”

“…Song and Li reviewed the recent advances in silver‐mediated intermolecular radical difunctionalizations of alkenes for the construction of C–C or C–X bonds leading to various cyclic and complex linear molecules [4] . Another Review by Anilkumar exclusively summarized various methods for the synthesis of six‐membered heterocyclic scaffolds using silver as a superlative catalyst [5] . The mechanism discussed in this review involves the initial coordination of silver to the substrate, followed by a 6‐ endo ‐ dig cyclization, to give the products.…”