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Impact of solvent polarity on N-heterocyclic carbene-catalyzed beta-protonations of homoenolate equivalents.

ABSTRACT: N-Heterocyclic carbenes have been demonstrated to react through divergent pathways under the same conditions. Experimental and computational evidence demonstrates that the ability to favor generation of homoenolate equivalents from alpha,beta-unsaturated aldehydes versus the oxidation of aldehydes to esters is highly dependent upon the choice of solvent. The solvation environment plays an important role due to the mechanistic differences in these processes, with polar protic solvent favoring the oxidation process due to solvation of intermediates with greater charge separation.

SUBMITTER: Maki BE

PROVIDER: S-EPMC2733935 | biostudies-literature | 2009 Sep

REPOSITORIES: biostudies-literature

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Impact of solvent polarity on N-heterocyclic carbene-catalyzed beta-protonations of homoenolate equivalents.

Maki Brooks E BE Patterson Eric V EV Cramer Christopher J CJ Scheidt Karl A KA

Organic letters 20090901 17

N-Heterocyclic carbenes have been demonstrated to react through divergent pathways under the same conditions. Experimental and computational evidence demonstrates that the ability to favor generation of homoenolate equivalents from alpha,beta-unsaturated aldehydes versus the oxidation of aldehydes to esters is highly dependent upon the choice of solvent. The solvation environment plays an important role due to the mechanistic differences in these processes, with polar protic solvent favoring the ...[more]

PMID: 19645427

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