Synthesis of spiropyrrolidines and spiropyrrolizidines by 1,3-dipolar cycloadditions of azomethine ylides to substituted a-methylene-g-lactones
| Autoři | |
|---|---|
| Rok publikování | 2001 |
| Druh | Článek v odborném periodiku |
| Časopis / Zdroj | Tetrahedron |
| Fakulta / Pracoviště MU | |
| Citace | |
| Obor | Organická chemie |
| Klíčová slova | cycloadditions; methylene lactones; azomethine ylides; regioselectivity; stereoselectivity |
| Popis | 1,3-Dipolar cycloadditions of (E)- and (Z)-substituted alpha -methylene-gamma -lactones with azomethine ylides derived from N-methyl glycine and L-proline gave the corresponding spiropyrrolidine and spiropyrrolizidine cycloadducts in good to moderate yields with various extent of stereoselectivity and regioselectivity. Cycloadditions of the azomethine ylide derived from L-proline exhibited endo selectivity especially in the case of (Z)-isomers of starting methylene lactones. Reactivity and regioselectivity were rationalized by a comparison with quantum chemical calculations (AM1). Structures of derivatives prepared were determined by NMR spectroscopy and by X-ray. |
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