67893-05-4Relevant articles and documents
Hydroacylation of α,β-unsaturated esters via aerobic C-H activation
Chudasama, Vijay,Fitzmaurice, Richard J.,Caddick, Stephen
scheme or table, p. 592 - 596 (2010/10/04)
The development of methods for carbon-carbon bond formation under benign conditions is an ongoing challenge for the synthetic chemist. In recent years there has been considerable interest in using selective C-H activation as a direct route for generating reactive intermediates. In this article, we describe the use of aldehyde auto-oxidation as a simple, clean and effective method for C-H activation, resulting in the generation of an acyl radical. This acyl radical can be used for carbon-carbon bond formation and herein we describe the application of this method for the hydroacylation of α,β-unsaturated esters without the requirement of additional catalysts or reagents. This methodology generates unsymmetrical ketones, which have been shown to have broad use in organic synthesis.
Photochimie en solution. XXIV. Mecanisme de l'addition des aldehydes aux double liaisons ethyleniques activees par des groupements attracteurs d'electrons
Kawenoki, Isabelle,Maurel, Daniele,Kossanyi, Jean
, p. 385 - 390 (2007/10/02)
The mechanism of the photochemical addition of aliphatic aldehydes to electron-deficient olefins has been rationalized.No addition to α,β-unsaturated ketones was observed when the latter were excited.The reaction can be explained by a first self-quenching step of the aliphatic aldehyde involving its lowest triplet state, which is reached with a moderate quantum yield (0.5).The radical R-C.=O produced in the self quenching process adds to the olefin at the more positively-charged carbon atom.The reaction ends by a hydrogen atom exchange between the radical produced by this addition and the radical R-C.HOH.The quantum yield of the product formation is much higher with benzaldehyde owing to the almost unity value of the intersystem crossing, but it competes with the formation of benzile.
