Selective Ring Contraction of 5-Spirocyclopropane Isoxazolidines Mediated by Acids
- 27 March 2003
- journal article
- Published by American Chemical Society (ACS) in The Journal of Organic Chemistry
- Vol. 68 (8) , 3271-3280
- https://doi.org/10.1021/jo034003g
Abstract
Thermolysis of 3,4-cis ring-fused 5-spirocyclopropane isoxazolidines 16, 18-21, 33, 34, 38a, and 61, in the presence of a protic acid at 70-110 degrees C, yielded 3,4-cis ring-fused azetidin-2-ones 22-26,41, 42, 46, and 62 with concomitant extrusion of ethylene, in good yields. So far, the collected evidences strongly support a mechanism started by a homolytic cleavage of the protonated N-O bond for the rearrangement of 5-spirocyclopropane isoxazolidines to beta-lactams. Some different competitive pathways can then follow depending on the stability or the stereoelectronic properties of cationic diradical intermediates. The two-step process, intramolecular 1,3-dipolar cycloaddition/thermal rearrangement under acidic conditions, represents a general synthesis of a new class of 3,4-cis-fused bicyclic azetidin-2-ones starting from easily available compounds such as amino acids, hydroxy acids, and dicarbonyl or amino alcohol derivatives.Keywords
This publication has 13 references indexed in Scilit:
- The powerful effect of N-aryl substitution in promoting the thermal rearrangement of 5-spirocyclopropaneisoxazolidinesTetrahedron Letters, 1999
- A new synthesis of (2S)-4-oxopipecolic acid by thermal rearrangement of enantiopure spirocyclopropaneisoxazolidineTetrahedron Letters, 1996
- Assignment of the Absolute Configuration of Natural Lentiginosine by Synthesis and Enzymic Assays of Optically Pure (+) and (-)-EnantiomersThe Journal of Organic Chemistry, 1995
- Intramolecular cycloadditions and thermal rearrangement of cyclopropylidene nitrones. Straightforward access to bicyclic tetrahydropyridonesTetrahedron Letters, 1995
- Synthesis of lentiginosine by stereoselective chiral nitrone cycloaddition and thermal rearrangement of strained spiroisoxazolidineTetrahedron Letters, 1994
- Rearrangement of isoxazoline-5-spiro derivatives. 8. Selective formation of tetrahydropyridones from C,C-disubstituted nitronesThe Journal of Organic Chemistry, 1992
- Rearrangement of isoxazoline-5-spiro derivatives. 5. Diastereofacial selectivity in the cycloaddition of substituted five-membered cyclic nitrones and methylenecyclopropanes. Stereoselective synthesis of 3,5-substituted indolizidinonesThe Journal of Organic Chemistry, 1990
- Rearrangement of isoxazoline-5-spiro derivatives. 2. Synthesis and rearrangement of tetrahydroisoxazole-5-spirocyclopropanes. Preparation of precursors of quinolizine, isoquinoline, and indole alkaloidsThe Journal of Organic Chemistry, 1988
- The pelletierine condensation. Mechanistic studiesThe Journal of Organic Chemistry, 1979
- The Constituents of Ecballium elaterium L. XI. Proposed Structures for α-Elaterin and its Degradation Products1,2Journal of the American Chemical Society, 1960