Regioselective Synthesis of 2‐(Trifluoromethyl)‐3‐ethoxycarbonyl‐4‐(2‐oxo‐2‐arylethyl)‐4H‐chromene Derivatives by [3, 3] Sigmatropic Rearrangement

A new and an efficient method has been developed to synthesize ethyl 4‐(2‐oxo‐2‐arylethyl)‐2‐(trifluoromethyl)‐4H‐chromene‐3‐carboxylate derivatives 3 from 2H‐chromene 1 and aryl acetylene 2 through [3, 3] sigmatropic rearrangement in presence of catalytic amount of BF3.OEt2 (10 mol %). In this repo...

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Bibliographic Details
Published in:ChemistrySelect (Weinheim) 2017-12, Vol.2 (35), p.11545-11547
Main Authors: Kuchukulla, Ratnakar Reddy, Desagoni, Madhu, Narra, Srikanth Reddy, Goutham, Santhosh Kumar, Banda, Narsaiah
Format: Article
Language:English
Subjects:
4H-chromene
acetylene
Aryl
Lewis acid
Regioselective
Sigma tropic rearrangement
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Summary:A new and an efficient method has been developed to synthesize ethyl 4‐(2‐oxo‐2‐arylethyl)‐2‐(trifluoromethyl)‐4H‐chromene‐3‐carboxylate derivatives 3 from 2H‐chromene 1 and aryl acetylene 2 through [3, 3] sigmatropic rearrangement in presence of catalytic amount of BF3.OEt2 (10 mol %). In this report an atom economy method is developed via [3, 3] sigmatropic rearrangement and best catalyst BF3.Et2O (10 mole %) is identified to drive the reaction smoothly by the catalyst screening. The Reaction time is short and carried at room temperature only. The high yield of the products (3 b, 3 e, 3 h, 3 k and 3 n) is attributed to the presence of electron withdrawing fluorine on para position of phenyl in acetylene.
ISSN:2365-6549
2365-6549
DOI:10.1002/slct.201701723