e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Hetero-Diels–Alder reactions of ketones: a high-yielding synthesis of 2, 2-disubstituted 2, 3-dihydropyran-4-ones
PCB Page, PH Williams, EW Collington…
Index: Page, Philip C. Bulman; Williams, P. Howard; Collington, Eric W.; Finch, Harry Journal of the Chemical Society, Chemical Communications, 1987 , p. 756 - 757
2,2-Disubstituted 2,3-dihydropyran-4-ones may be prepared in high yields by the Lewis acid-catalysed hetero-Diels-Alder reactions of electron-rich dienes with ketones bearing strongly electron-withdrawing substituents. ... As a part of our interest in tetrahydropyrones we required a general high-yielding preparative method for 2,2-disub- stituted 2,3-dihydropyran-4-ones (1). A number of syntheses of pyran-4-ones appear in the literature,l for example the ...