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Metal‐ and Catalyst‐Free One‐Pot Cascade Coupling of α‐Enolic Dithioesters with in situ Generated 4‐Chloro‐3‐formylcoumarin: Access to Thioxothiopyrano[3,2‐ c ]chromen‐5(2 H )‐ones
Author(s) -
Yadav Dhananjay,
Ansari Monish A.,
Kumar Mitilesh,
Singh Maya Shankar
Publication year - 2020
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201901180
Subject(s) - chemistry , intramolecular force , cascade , catalysis , ring (chemistry) , combinatorial chemistry , cascade reaction , medicinal chemistry , photochemistry , stereochemistry , organic chemistry , chromatography
Abstract An efficient and viable one‐pot protocol for the synthesis of a specific class of 2‐thioxothiopyrano[3,2‐ c ] chromen‐5(2 H )‐ones has been devised by the cross‐coupling of 4‐hydroxycoumarin and α‐enolic dithioesters under metal‐ and additive‐free conditions in open air. The reaction proceeds via in situ generation of 4‐chloro‐3‐formylcoumarin followed by consecutive Michael‐type addition/intramolecular cyclization/ elimination cascade, enabling the creation of thiopyran‐2‐thione ring over coumarin framework through successive formation of C−C and C−S bonds. Remarkably, the benign conditions, atom‐economy, and quantifying forbearance of a wide horizon of functional groups are added characteristics to this strategy.