Abstract
A great variety of pharmacologically relevant fluorinated purine analogues are available
by cyclization reactions of heterocyclic enamines with 1,3-dielectrophiles. The reactions
usually proceed with excellent regioselectivities. As electrophiles, 1,3-diketones,
enaminones or 3-chloro-2-en-1-ones were used. Other synthetic strategies are based
on inverse-electron-demand Diels–Alder reactions of heterocyclic enamines with triazines.
Purine analogues were further functionalized by transition-metal-catalyzed CH-coupling
reactions or oxidative cyclizations, giving rise to more complex polycyclic products.
Amidino-C-glycosides in their reactions with 1,3-dielectrophiles afforded pyrimidine-C-glycosides. Multicomponent reactions of heterocyclic enamines afforded complex products,
including spirocyclic derivatives.
1 Introduction
2 1,3-Diketones
3 Enaminones
4 3-Chloro-2-en-1-ones
5 Triazines
6 Transition-Metal-Catalyzed Functionalizations
7 Pyrimidine-C-Nucleosides
8 Multicomponent Reactions
9 Conclusions
Key words
enamines - cyclization - 1,3-dielectrophiles - heterocycles - purines - regioselectivity