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N-heterocyclic carbene-catalyzed conjugate additions of alcohols.

ABSTRACT: An efficient intermolecular conjugate addition of alcohols to activated alkenes catalyzed by N-heterocyclic carbenes has been developed. With 5 mol % of the free carbene derived from IMes·HCl, unsaturated ketones and esters are competent substrates, and a variety of primary and secondary alcohols can be employed as the nucleophile. No oligomerization is observed under these mild conditions for effective hydroalkoxylation. In addition to reactions with activated alkenes, IMes catalyzes the formation of vinyl ethers through the 1,4-addition of alcohols to ynones and promotes tandem conjugate addition/Michael cascade reactions. Preliminary data support a Brønsted base mechanism with the free carbene.

SUBMITTER: Phillips EM

PROVIDER: S-EPMC2944903 | biostudies-literature | 2010 Sep

REPOSITORIES: biostudies-literature

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N-heterocyclic carbene-catalyzed conjugate additions of alcohols.

Phillips Eric M EM Riedrich Matthias M Scheidt Karl A KA

Journal of the American Chemical Society 20100901 38

An efficient intermolecular conjugate addition of alcohols to activated alkenes catalyzed by N-heterocyclic carbenes has been developed. With 5 mol % of the free carbene derived from IMes·HCl, unsaturated ketones and esters are competent substrates, and a variety of primary and secondary alcohols can be employed as the nucleophile. No oligomerization is observed under these mild conditions for effective hydroalkoxylation. In addition to reactions with activated alkenes, IMes catalyzes the format ...[more]

PMID: 20809579

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