CHAPTER 6: Serebryakov–Jørgensen Dienamines (1-Aminobuta-1,3-Dienes): Different In situ Generation Methods and Applications in [2+2], [3+2] and a Few Other Cycloadditions

Serebryakov–Jørgensen dienamines (1-aminobuta-1,3-dienes) have applications in several cycloadditions, such as [2+2]- and [3+2]-cycloadditions, and have furnished a broad spectrum of various structurally complex cyclobutanes, cyclopentanecarbaldehydes, tetrahydroquinolines, highly functionalized cyclohexenals and 8-oxabicyclo[3.2.1]octane frameworks with complete regio-, diastereo- and enantio-selectivity. The electron-rich dienamines formed invariably from enolizable α,β-unsaturated aldehydes, allyl ketones, substituted cyclopropylacetaldehydes and cyclic enones reacted as the 2π-reaction partners in [2+2]- and [3+2]-cycloadditions with electrophilic partners, including nitroolefins, α-hydroxymethylnitrostyrenes, methyleneindolinones and substituted C,N-cyclic azomethine imines. Moreover, the [3+2]-cycloaddition of these dienamine intermediates with azides created easy access to 1,4-disubstituted- and 1,4,5-trisubstituted-1,2,3-triazoles. Both cyclobutanes and five-membered ring systems are essential part structures of many natural products, as well as biologically and medicinally important compounds. Further, these in situ formed dienamine intermediates have been investigated for enantioselective [5+2]-cycloadditions, and formal [3+3]- and [5+3]-cycloadditions too.