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. 2010 Sep 29;132(38):13179-81.
doi: 10.1021/ja1061196.

N-heterocyclic carbene-catalyzed conjugate additions of alcohols

Eric M Phillips  1 , Matthias Riedrich, Karl A Scheidt
Affiliations

N-heterocyclic carbene-catalyzed conjugate additions of alcohols

Eric M Phillips et al. J Am Chem Soc. .

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.

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Figures

Scheme 1
Scheme 1
NHC-Catalyzed Conjugate Additions
Scheme 2
Scheme 2
Proposed Pathway
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