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Chiral Inductive Diastereoconvergent Friedel–Crafts Alkylation Reaction of Diastereomixtures of Diarylmethanols with 2‐Naphthol Derivatives Catalyzed by SnBr 4
Author(s) -
Suzuki Nobuharu,
Nakata Kenya
Publication year - 2017
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.201701280
Subject(s) - chemistry , friedel–crafts reaction , alkylation , carbocation , catalysis , chirality (physics) , chiral auxiliary , asymmetric induction , diastereomer , nitromethane , organic chemistry , electrophilic aromatic substitution , sn2 reaction , medicinal chemistry , enantioselective synthesis , chiral symmetry breaking , physics , quantum mechanics , nambu–jona lasinio model , quark
A highly diastereoconvergent Friedel–Crafts alkylation reaction of 2‐naphthol derivatives with diastereomixtures of diarymethanols bearing a designed chiral auxiliary was achieved by using tin(IV) bromide as a catalyst in nitromethane under mild reaction conditions. The effects of various substituents located on the chiral auxiliary were evaluated, and chiral induction was found to take place via a carbocation through the chelation effect of an oxygen atom in a stereoconvergent manner. The chiral auxiliary was easily deprotected under conventional hydrogenation conditions without affecting the chirality of the starting material. A variety of substrates were transformed successfully, with high yields and selectivities (diastereomeric ratios ≥ 20:1) obtained irrespective of the substitution pattern and the electronic nature of the substrate aromatic rings.