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Studies on the Intermolecular Hydroarylation of N ‐Ts‐ or N ‐Ac‐Protected Indoles and 2,3‐Allenoates
Author(s) -
Fang Zhao,
Fu Chunling,
Ma Shengming
Publication year - 2011
Publication title -
european journal of organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 1434-193X
DOI - 10.1002/ejoc.201001661
Subject(s) - carbocation , chemistry , regioselectivity , allylic rearrangement , intermolecular force , selectivity , friedel–crafts reaction , medicinal chemistry , stereochemistry , organic chemistry , molecule , catalysis
Abstract An operationally simple, TFA‐promoted regioselective hydroarylation reaction of 2,3‐allenoates with N ‐Ts‐ or N ‐Ac‐indoles to afford 4‐indolyl‐4‐arylbut‐2‐enoates is described. A series of substrates was tested, and the E / Z selectivity was found to depend on the reaction temperature and time. A mechanism involving the formation of E and Z allylic carbocations generated in situ from the reaction of 2,3‐allenoate with TFA and subsequent Friedel–Crafts attack at the 3‐position of the indoles was proposed to explain the results.