Recent developments in the enantioselective synthesis of polyfunctionalized pyran and chromene derivatives

Acid‐modified Halloysite Nanotubes as a Stereoselective Catalyst for Synthesis of 2H‐Chromene Derivatives by the Reaction of Isopulegol with Aldehydes

“…It is known that compounds with a chromene (benzopyran) scaffold have a broad spectrum of biological activity . A high pharmaceutical potential and low toxicity of these substances resulted in a considerable interest in the synthesis of new chromene derivatives .…”

Zn(L-proline)2: An efficient and reusable organocatalyst for the synthesis of polyfunctionally substituted pyrans and 2-amino-4-aryl-8-oxo-4,8-dihydropyrano[3,2-b]pyran derivatives

“…One such protocol involves the use of cheap, recyclable and easy handle catalyst. In continuation of our efforts [21][22][23][24][25][26] aimed at performing reactions under green conditions we reported herein efficient three-component domino reaction for the synthesis of nonannulated 2-amino-4H-pyrans and 2-amino-8-oxo-4,8-dihydro pyrano[3,2-b]pyran derivatives via reaction of aromatic aldehydes, malononitrile and ethyl acetoacetate or kojic acid catalyzed by Zn(L-proline)2 as soft Lewis acid.…”

Facile One‐pot Synthesis of Arylsulfonyl‐4H‐pyrans Catalyzed by Ru Loaded Fluorapatite

“…[30][31][32][33][34][35][36][37][38] Furthermore, these moieties have vital importance in the fields of agrochemicals, cosmetics and the pigment production. [39,40] In the recent past, various methodologies have been reported for synthesis of diverse pyran derivatives using different catalysts including, N (CH 3 ) 4 OH, NaBr, I 2 , L-proline, phenylboronic acid, tri-sodium citrate, piperidine and cerium-(III)-chloride. [41][42][43][44][45][46][47][48] However, those procedures generally suffer with several drawbacks, such as toxicity, prolong reaction times, hazardous organic solvents, lower yields, a tedious work-up, non-recyclability and harsh reaction conditions.…”

“…Most of these structural moieties, exhibit diverse medicinal properties, including antimicrobial, anti‐viral, anti‐allergenic, anti‐tumor, anti‐inflammatory, anti‐coagulant, anti‐ oxidant, anti‐Parkinson's and Alzheimer's disease activities . Furthermore, these moieties have vital importance in the fields of agrochemicals, cosmetics and the pigment production . In the recent past, various methodologies have been reported for synthesis of diverse pyran derivatives using different catalysts including, N(CH 3 ) 4 OH, NaBr, I 2 , L‐proline, phenylboronic acid, tri‐sodium citrate, piperidine and cerium‐(III)‐chloride .…”