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Aluminum enolates via retroaldol reaction: catalytic tandem aldol-transfer—Tischtschenko reaction of aldehydes with aldol adducts of ketones to ketones

✍ Scribed by Ilkka Simpura; Vesa Nevalainen


Book ID
104205719
Publisher
Elsevier Science
Year
2003
Tongue
French
Weight
475 KB
Volume
59
Category
Article
ISSN
0040-4020

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✦ Synopsis


Bidentate aluminum chelates derived from biphenol, binaphthol and catechol were found to be efficient catalysts for aldoltransfer reactions of ketone to ketone aldol adducts with aliphatic or aromatic aldehydes giving rise to the formation of aldol adducts of ketones to the aldehydes. In the presence of an excess of an aliphatic aldehyde, a catalytic tandem aldol-transfer-Tischtschenko reaction is observed. The tandem reaction produces monoesters of 1,3-diols with high anti selectivity and with modest to good chemical yield. 1,2-Unsaturated aldehydes are less reactive in the aldol-transfer reaction and require 2 -4 times higher load of the catalyst to be used than aliphatic and aromatic aldehydes. Poor diastereoselectivity was observed in the formation of a-substituted aldols and 2-substituted monoesters of anti-1,3-diols indicating that the aldol-transfer reaction is not diastereoselective with the catalysts studied. The utility of the highly 1,3-anti selective formation of diolmonoesters was found to be limited by acyl migration.


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