Abstract
Metallo-azomethine ylides, generated from imines by the action of amine bases in combination with LiBr or AgOAc, undergo cycloaddition with both 1R, 2S, 5R- and 1S, 2R, 5S-menthyl acrylate at room temperature to give homochiral pyrrolidines in excellent yield. The stronger the base the faster the cycloaddition and the greater the yield with: 2-t-butyl-1,1,3,3-tetramethylguanidine > DBU > NEt(3) X-Ray crystal structures of representative cycloadducts establish that the absolute configuration of the newly established pyrrolidine stereocentres is independent of the metal salt and the size of the pyrrolidineC(2)-substituent for a series of aryl and aliphatic imines.
Original language | English |
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Pages (from-to) | 273-294 |
Number of pages | 22 |
Journal | Tetrahedron |
Volume | 51 |
Issue number | 1 |
Publication status | Published - 02 Jan 1995 |
Keywords
- CHIRAL AZOMETHINE YLIDES
- ALPHA-AMINO ESTERS
- CYCLO-ADDITION REACTIONS
- DIELS-ALDER REACTIONS
- DIASTEREOFACIAL SELECTIVITY
- SYSTEMS
- INDUCTION
- PYRROLIDINES
- GENERATION
- MECHANISMS