| Abstract
| - Racemic as well as optically pure 2-azetidinone-tethered nitrones, both cyclic and acyclic, weresmoothly prepared from 4-oxoazetidine-2-carbaldehydes. The regio- and diastereoselectivities ofthe intermolecular 1,3-dipolar cycloaddition reactions of 2-azetidinone-tethered nitrones withsubstituted alkenes and alkynes were investigated. 2-Azetidinone-tethered nitrones on reactingwith various dipolarophiles yielded isoxazolinyl-, isoxazolidinyl-, or fused polycyclic-β-lactams,exhibiting good regio- and facial stereoselectivity in the most of the cases. In addition, someinteresting transformations of these cycloadducts were performed, yielding aziridinyl β-lactams orfunctionalized β-alkoxycarbonyl γ-lactams (derivatives of the aza analogue of paraconic acid).
|
