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The Zirconium Alkoxide‐Catalyzed Aldol‐Tishchenko Reaction of Ketone Aldols
Author(s) -
Schneider Christoph,
Hansch Markus,
Weide Timo
Publication year - 2006
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.200400951
Subject(s) - aldol reaction , alkoxide , ketone , zirconium , chemistry , catalysis , enol , organic chemistry , lewis acids and bases , lewis acid catalysis
The aldol‐Tishchenko reaction of ketone aldols as enol equivalents has been developed as an efficient strategy to furnish differentiated 1,3‐ anti ‐diol monoesters in one step. The thermodynamically unstable ketone aldols undergo a facile retro‐aldolization to yield a presumed zirconium enolate in situ, which then undergoes the aldol‐Tishchenko reaction in typically high yields and with complete 1,3‐ anti diastereocontrol. Evaluation of a broad range of metal alkoxides as catalysts and optimization of the reaction protocol led to a modified zirconium alkoxide catalyst with attenuated Lewis acidity and dichloromethane as solvent, which resulted in suppression of the undesired acyl migration to a large extent. Various ketone aldols have been prepared and subjected to the general process, giving rise to a broad range of differently substituted 1,3‐ anti ‐diol monoesters, which may be hydrolyzed to the corresponding 1,3‐ anti ‐diols.