Synthetic protocols on 6$H$-benzo[$c$]chromen-6-ones: a review

Abstract

6 H -Benzo[ c ]chromen-6-ones serve as core structures of secondary metabolites and are of considerable pharmacological importance. Natural sources produce limited quantities, hence the need for synthetic procedures for 6 H -benzo[ c ]chromen-6-ones, which are herein reviewed. The literature describes protocols such as the Suzuki coupling reactions for the synthesis of biaryl, which then undergoes lactonization, reactions of 3-formylcoumarin (chromenones) with 1,3-bis(silylenol ethers), radical mediated cyclization of arylbenzoates, metal or base catalyzed cyclization of phenyl-2-halobenzoates and 2-halobenzyloxyphenols, and benzoic acid coupling with benzoquinone using electrophilic metalbased catalyst. The efficient and simple procedures are those involving the reactions of Michael acceptor (chromenones and chalcones) with 1,3-and 1,5-dicarbonyl compounds.

Microwave-Assisted Cyclization under Mildly Basic Conditions: Synthesis of 6H-Benzo[c]chromen-6-ones and Their 7,8,9,10-Tetrahydro Analogues

“…It is known that many naturally occurring 6 H -benzo­[ c ]­chromen-6-ones exhibit diverse biological activities. , Thus, many synthetic methods have been developed and documented for such 6 H -benzo­[ c ]­chromen-6-ones due to limited quantities of natural sources . It is reported that such a scaffold can be synthesized by copper­(I) thiophene carboxylate (CuTC)-mediated lactonization of 2′-halobiphenyl-2-carboxylic acids and Lewis acid-mediated lactonization of 2′-methoxybiphenyl-2-carboxylic acids and methyl 2′-methoxybiphenyl-2-carboxylates (Scheme , route a). , Deng et al also demonstrated palladium/copper-catalyzed decarboxylative coupling and cyclization of 2-nitrobenzoic acids with methyl 2-halobenzoates leading to 6 H -benzo­[ c ]­chromen-6-ones (Scheme , route b) .…”

Cascade Lactonization/Benzannulation of Propargylamines with Dimethyl 3-Oxoglutarate for Modular Assembly of Hydroxylated/Arene-Functionalized Benzo[c]chromen-6-ones

“…Numerous approaches allowing the synthesis of benzo [c]chromen-6-one have been reported. 6 For instance, Baeyer− Villiger oxidation of fluorenone 7 and transition-metal-catalyzed tandem coupling reactions have been found as precedent. 8 A few free-radical-mediated syntheses, multicomponent strategies, and other procedures were also demonstrated recently.…”