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Catalytic Friedel‐Crafts Reactions on Saturated Heterocycles and Small Rings for sp 3 ‐sp 2 Coupling of Medicinally Relevant Fragments
Author(s) -
Croft Rosemary A.,
Dubois Maryne A. J.,
Boddy Alexander J.,
Denis Camille,
Lazaridou Anna,
VoisinChiret Anne Sophie,
Bureau Ronan,
Choi Chulho,
Mousseau James J.,
Bull James A.
Publication year - 2019
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.201900498
Subject(s) - chemistry , catalysis , cyclobutanes , friedel–crafts reaction , nucleophile , alcohol , substrate (aquarium) , medicinal chemistry , organic chemistry , stereochemistry , combinatorial chemistry , cycloaddition , oceanography , geology
gem ‐Diarylheterocycles display a wide range of biological activity. Here we present a systematic study into the formation of 4‐ to 6‐membered O‐ and N‐heterocycles and cyclobutanes bearing the diaryl motif through a catalytic Friedel–Crafts reaction from the corresponding benzylic alcohols. 3,3‐Diaryltetrahydrofurans, 4,4‐diaryltetrahydropyrans, 3,3‐diarylpyrrolidines, 4,4‐diaryl‐piperidines, as well as diarylcyclobutanes are examined, with results for 3,3‐diaryloxetanes and 3,3‐diarylazetidines presented for comparison. Three catalytic systems are investigated for each substrate [Ca(II), Li(I) and Fe(III)], across preinstalled aromatic groups of differing electronic character. In most cases examined, the diaryl product is obtained directly from the alcohol with good yields using the most appropriate catalyst system. In the absence of a nucleophile, the olefins from the 5‐ and 6‐membered substrates by elimination of water are obtained under the same reaction conditions.