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Asymmetric Friedel–Crafts Alkylations of Indoles with Ethyl Glyoxylate Catalyzed by ( S )‐BINOL‐Titanium(IV) Complex: Direct Access to Enantiomerically Enriched 3‐Indolyl(hydroxy)acetates
Author(s) -
Dong HongMing,
Lu HaiHua,
Lu LiangQiu,
Chen CaiBao,
Xiao WenJing
Publication year - 2007
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.200600495
Subject(s) - chemistry , glyoxylate cycle , friedel–crafts reaction , enantioselective synthesis , catalysis , yield (engineering) , alkylation , enantiomer , enantiomeric excess , organic chemistry , titanium , medicinal chemistry , enzyme , materials science , metallurgy
Enantioselective Friedel–Crafts alkylation reactions of a variety of indoles with ethyl glyoxylate, catalyzed by a chiral ( S )‐BINOL‐Ti(IV) complex (10 mol %), are reported. The corresponding ethyl 3‐indolyl(hydroxy)acetates were formed in good yields and with high enantiomeric excess (up to 96 %). When methyl pyruvate or p ‐chlorophenylglyoxal was used, the bisindole compound was obtained in excellent yield. A possible mechanism is proposed.