Asymmetric pyrone Diels–Alder reactions enabled by dienamine catalysis. Issue 8 (22nd January 2020)

• Record Type: Journal Article
• Authors: Cole, Charles J. F.; Fuentes, Lilia; Snyder, Scott A.
• Is Part Of: Chemical science. Volume 11:Issue 8(2020)
• Page Start: 2175
• Page End: 2180
• Publication Date: 2020-01-22
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c9sc05738b
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : A dienamine mediated asymmetric Diels–Alder reaction between an array of α, β-unsaturated enals and electron-deficient pyrones is presented along with further transformations of the obtained products and models for the observed stereoselectivity. Abstract : Despite the proven value in utilizing pyrone dienes to create molecular complexity via Diels–Alder reactions with varied dienophiles, few examples of effective catalytic, asymmetric variants of this process have been developed. Herein, we show that the use of Jørgensen–Hayashi-type catalysts can convert an array of α, β-unsaturated aldehydes into chiral dienamines that can formally add in a Diels–Alder fashion to a number of electron-deficient pyrones of the coumalate-type to generate optically active [2.2.2]-bicyclic lactones. In most cases, the reactions proceed with good to excellent diastereo- and enantiocontrol (up to 99% ee). Models to explain that stereoselectivity, as well as several additional transformations of the resultant products, are also presented.