Synthesis of spiropyrrolidines and spiropyrrolizidines by 1,3-dipolar cycloadditions of azomethine ylides to substituted a-methylene-g-lactones
| Authors | |
|---|---|
| Year of publication | 2001 |
| Type | Article in Periodical |
| Magazine / Source | Tetrahedron |
| MU Faculty or unit | |
| Citation | |
| Field | Organic chemistry |
| Keywords | cycloadditions; methylene lactones; azomethine ylides; regioselectivity; stereoselectivity |
| Description | 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. |
| Related projects: |