α-Diketones as acyl anion equivalents: A non-enzymatic thiamine-promoted route to aldehyde-ketone coupling in PEG400 as recyclable medium

Abstract:

By mimicking the peculiar behavior of thiamine diphosphate-dependent acetylacetoin synthase, it has been demonstrated that thiamine hydrochloride 2a and its simple analogue thiazolium salt 2b are able to activate α-diketones as acyl anion equivalents in nucleophilic acylations, such as the homo-coupling of α-diketones and the hitherto unreported cross-coupling between α-diketones and α-ketoesters. These carboligation reactions were optimized under stoichiometric (2a) and catalytic conditions (2b) by using eco-friendly PEG<inf>400</inf> as the reaction medium, thus allowing both solvent and thiazolium salt recycling. © 2011 Elsevier Ltd. All rights reserved.

Año de publicación:

2011

Keywords:

• α-Diketones
• α-Hydroxyketones
• N-Heterocyclic carbenes
• Polyethylene glycol
• Thiazolium salts

Fuente:

scopus