e.g. Filippa Pettersson or Cancer Res. 75(6) , 1102-12, (2015) or 10.1002/anie.201600521
Studies of intramolecular Diels-Alder reactions: preparation of methyl spiro [2.4] hepta-4, 6-dien-1-yl esters and their internal cycloaddition reactivity
…, SK Attah-Poku, K Antczak, SJ Alward…
Index: Gallacher, Gerard; Ng, Ang Ser; Attah-Poku, Samuel K.; Antczak, Kazimierz; Alward, Sandra J.; et al. Canadian Journal of Chemistry, 1984 , vol. 62, p. 1709 - 1716
Different routes to the spiro [2.4] hepta-4, 6-dien-1-yl esters 5, 6, 7, 26, and 28 are described and their intramolecular Diels-Alder reactivity examined. A sidechain oxygen substituent is essential for cyclization although its exact role in the cycloaddition remains obscure. The trienes 5, 6, and 28 cyclize to the tetracyclo [5.4. 01.7. 04.6. 06.10] undecenes 9, 10, and 30 which are useful synthetic intermediates for the preparation of sesquiterpenes.