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Chalcogenide‐Lewis Acid Mediated Reactions of Electron‐Deficient Alkynes with Aldehydes
Author(s) -
Kinoshita Sayaka,
Kinoshita Hironori,
Iwamura Tatsunori,
Watanabe Shinichi,
Kataoka Tadashi
Publication year - 2003
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200390169
Subject(s) - chemistry , lewis acids and bases , medicinal chemistry , aldol reaction , dimethyl acetylenedicarboxylate , yield (engineering) , demethylation , sulfide , hydroxymethyl , organic chemistry , catalysis , cycloaddition , biochemistry , materials science , dna methylation , gene expression , metallurgy , gene
Reactions of but‐3‐yn‐2‐one ( 2 ) with aldehydes 1 in the presence of a Lewis acid and dimethyl sulfide ( 3 a ) predominantly gave ( E )‐ α ‐(halomethylene)aldols 4 – 5 in high yields, while reactions of methyl propiolate ( 6 a ) mainly afforded ( Z )‐3‐halogeno‐2‐(hydroxymethyl)acrylates 7 – 8 in low to moderate yields. A reaction of dimethyl acetylenedicarboxylate ( 10 ) with 1 a in the presence of TiCl 4 and 1,1,3,3‐tetramethylthiourea ( 3 c ) produced maleate ( E )‐ 11 (40 %) and butenolide 12 (40 %). When a reaction of 6 a with 1 a was carried out in the presence of TiBr 4 and 3 a (0.2 equiv) at −20 °C for 60 h, 3‐(methylthio)‐2‐(hydroxyalkyl)acrylate 9 a was obtained in an 8 % yield. Experiments were conducted in order to elucidate the formation mechanism of 9 a , and it was made clear that 9 a was formed via the processes of the Michael addition of sulfide 3 a to alkynoate 6 a and an aldol reaction with 1 a and demethylation.
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