Amine-promoted asymmetric (4+2) annulations for the enantioselective synthesis of tetrahydropyridines: A traceless and recoverable auxiliary strategy

Article abstract of DOI:10.1002/anie.201300526

Gone, without a trace: The in situ reaction of 2-(acetoxymethyl)buta-2,3- dienoate and a secondary amine produces a 2-methylene-3-oxobutanoate equivalent that can be used in asymmetric [4+2] annulations with N-tosylimines to provide tetrahydropyridines in