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Zn(II) Chloride Promoted Benzannulation Strategy for One‐Pot Regioselective Synthesis of 6 H ‐Benzo[ c ]chromenes
Author(s) -
Muralidhar Baitinti,
Reddy Sabbasani Rajasekhara
Publication year - 2017
Publication title -
chemistryselect
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.437
H-Index - 34
ISSN - 2365-6549
DOI - 10.1002/slct.201700311
Subject(s) - regioselectivity , chemistry , alkyne , cycloaddition , chloride , medicinal chemistry , catalysis , reaction conditions , organic chemistry , combinatorial chemistry
A facile highly regioselective Zn(II) chloride promoted protocol for the synthesis of polycyclic chromene derivatives ( 6H ‐benzo[ c ]chromenes) is described starting from 4‐(phenylethynyl)‐2 H ‐chromene‐3‐carbaldehydes ( 1 ) and terminal alkynes ( 2 ). The reaction proceeds through a formal [4+2] cycloaddition between an intermediate formed in situ between 1, Zn(II) chloride and alkyne ( 2 ) followed by a retro Diels‐Alder step. Developed method provides the desired heterocyclic compounds in high yields under mild reaction conditions.