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Fe‐catalyzed hydrohalogenative cyclization of cyclohexadienone‐containing enynes
Author(s) -
Hong YaChun,
Santhoshkumar Rajagopal,
Cheng ChienHong
Publication year - 2019
Publication title -
journal of the chinese chemical society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.329
H-Index - 45
eISSN - 2192-6549
pISSN - 0009-4536
DOI - 10.1002/jccs.201900292
Subject(s) - chemistry , halide , stereoselectivity , catalysis , stoichiometry , reactivity (psychology) , aryl , medicinal chemistry , alkyl , organic chemistry , medicine , alternative medicine , pathology
A Fe‐catalyzed hydrohalogenative cyclization of cyclohexadienone‐containing 1, n ‐enynes to give three different types of compounds is discussed. 1,6‐enynes with a stoichiometric amount of FeX 3 provided cis‐hydrobenzofurans with moderate stereoselectivity, whereas the reaction with TMSX (X = Cl, Br) as the halide source in the presence of Fe catalyst improved the stereoselectivity of halide addition highly. The alkyl vs aryl shows difference that the reaction of 1,6‐enynes bearing an alkylethynyl group gave meta alkenated phenols (2 examples) whereas a similar reaction of 1,6‐enynes with an arylethynyl group delivered only cis ‐hydrobenzofurans (12 examples). 1,7‐enynes afforded tricyclic products (4 examples). The different reactivity of 1,6‐ and 1,7‐enynes is probably influenced by the formation of a six‐membered chair‐like intermediate in 1,6‐enynes.