stereoselective synthesis of 4-aminotetrahydropyridines by cycloaddition reaction of 2-amino-1,3-butadienes with N-alkyl and N-aryliminoesters in the presence of a catalytic amount of a Lewis acid is described. The reaction proceeds with differently substituted 2-aminodienes, giving rise to structurally diverse pipecolic acid derivatives.
Under specific reaction conditions only the terminal Ctriple bond of several alk-3-en-1-ynes adds amines, viacatalyticaminomercuriation, to afford 1-aza- and 2-morpholino-1,3-dienes.
A new type of cyclic amino-functionalized s-cis boroxyvinylcarbene complex of group 6 metals has been synthesized. These complexes underwent Diels−Alder-type reactions with 2-amino 1,3-dienes that proceeded with complete regioselectivity and high exo or endo diastereoselectivity, which was found to be highly dependent on the nature of the substituents on the diene. When chiral 2-amino-5-alkoxy dienes
2-Morpholinobutadienes have been found to show different behaviour in the reaction with isocyanates and isothiocyanates. While isocyanates give rise always to openchain compounds, isothiocyanates yield mainly thiin1 derivatives.
Stereospecific [4+2] Reaction between 2-Morpholino-1,3-butadienes and α,β-Unsaturated Exocyclic Chromium Carbene Complexes. Preparation of Enantiomerically Pure Spiro Compounds
A stereospecific exoselective [4+2] reaction between α,β-unsaturated exocyclic chromium carbene complexes and 2-amino-1,3-butadienes is described. Its application employing homochiral carbene complexes gives rise to the optically pure spiro-lactones.