Work

Enantioselective Synthesis of α,α-Disubstituted Cyclopentenes by an N-Heterocyclic Carbene-Catalyzed Desymmetrization of 1,3-Diketones

Year: 2007

Type: article

Abstract: The enantioselective synthesis of α,α-disubstituted cyclopentenes using N-heterocyclic carbene catalysis is reported. This desymmetrization reaction proceeds via a chiral enol generated in situ from the combination of an enantiopure azolium salt and α,β-unsaturated aldehyde. This reactive enol undergoes addition to one of two enantiotopic ketones to afford an optically active β-lactone after the intermediate carbinol is involved in an internal acylation event to release the carbene catalyst. In the substrates where R = aryl, a decarboxylation occurs immediately after lactone formation to produce the quaternary center-containing cyclopentene products in up to 96% ee. When the R group is alkyl, the β-lactones are isolated in moderate yield and high diastereo- and enantioselectivity.

Source: Journal of the American Chemical Society

DOI: 10.1021/ja073987e

Authors: Manabu Wadamoto, Eric M. Phillips, Troy E. Reynolds, Karl A. Scheidt

Institution: Northwestern University

Language: English

Topic: N-Heterocyclic Carbenes in Organic and Inorganic Chemistry

Subfield: Organic Chemistry

Field: Chemistry

Domain: Physical Sciences

Open Access status: green

Funders: National Science Foundation, Amgen, National Institute of General Medical Sciences, Division of Chemistry

Awards: G344074598, G682315649