Diels−Alder Reactions of Chiral 1,3-Dienes

Autor:	Markus G. Gebauer, Geoffrey T. Crisp
Rok vydání:	1996
Předmět:	chemistry.chemical_compound Diene Chemistry Asymmetric carbon Organic Chemistry Diels alder Maleic anhydride Ether Protecting group Selectivity Medicinal chemistry Adduct
Zdroj:	The Journal of Organic Chemistry. 61:8425-8431
ISSN:	1520-6904 0022-3263
Popis:	Structurally related 1,3-dienes 3a−f attached to a chiral carbon were treated with maleic anhydride under a variety of conditions. The initial Diels−Alder adducts were not isolated as they spontaneously rearranged to the isomeric isoindolones 6 and 7. The rate of the rearrangement was dependent on the relative stereochemistry of the initial cycloadducts. The π-facial selectivity of the Diels−Alder reaction was determined by analyzing reaction mixtures of the isomeric isoindolones by 1H and 13C NMR spectroscopy and HPLC. A gradual increase in the π-facial selectivity was observed when the homoallylic hydroxyl group of the diene was endowed with a larger protecting group or slightly increased by performing the reactions in ether saturated with LiClO4. These effects were rationalized by proposing a model based on 1,3-allylic strain in the transition state for the dienes 3a−f.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::b7793b0ab5508153f1b1fdbeae2370aa https://doi.org/10.1021/jo9609743 Zobrazit plný text záznamu