CHAPTER 4: Ramachary's Dienamines (Push-Pull Dienamines): In situ Generation and Applications

Abstract

Ramachary's push-pull dienamines, prepared in situ from Hagemann's esters, have participated efficiently in many cascade sequences, such as the Claisen-Schmidt condensation, enamine amination/isoaromatization (EA/IA), Claisen-Schmidt/isomerization, Claisen-Schmidt/Michael reactions, Claisen-Schmidt/Henry (CS/H) reactions and multi-catalysis cascade reactions. The synthesis of highly functionalized phenols, o-pyrrolidine-1-yldiarylamines, o-hydroxydiarylamines, (Z)-2-(buta-1,3-dienyl)phenols, 2-methyl-2H-chromenes, (E)-1,3-dienes, dienones, chromenone, benzoxazocines and terpenoid-type chiral decalines was accomplished through push-pull dienamine intermediates. Further, these were applied in the synthesis of medicinally important nefopam analogues. Highly functionalized NH-1,2,3-triazoles and 1,4,5-trisubstituted-1,2,3-triazoles were also accessed via [3+2]-cycloaddition. In addition, upon Michael addition with β-nitrostyrenes, push-pull dienamines produced Baylis-Hillman-type products.