A novel and unexpected one pot synthesis of pyrrolo[1,2-a]quinolines

Base-Mediated Cascade Lactonization/1,3-Dipolar Cycloaddition Pathway for the One-Pot Assembly of Coumarin-Functionalized Pyrrolo[2,1-a]isoquinolines

“…Heterocyclic scaffolds are ubiquitous in natural products, pharmaceutical lead molecules, dyes, and functional materials . More specifically, pyrrolo­[2,1- a ]­isoquinoline species have attracted significant attention, in which they not only are one of the most important classes of structural motifs but also are found in various natural alkaloid products with a wide spectrum of bioactivities. , In this regard, great efforts have been made for straightforward construction of the pyrrolo­[2,1- a ]­isoquinoline scaffold from both the formation of a pyrrole framework on the existing isoquinoline ring through including 1,3-dipolar cycloaddition, [3 + 2] cycloaddition reactions, multicomponent reactions, and other reactions, as well as assembly of an isoquinoline unit on the existing pyrrole ring . On the other hand, coumarin as one of the most advantageous scaffolds is widely applied in the field of medicinal chemistry and materials science .…”

Recent advances in the synthesis of chromenone fused pyrrolo[2,1-a]isoquinoline derivatives

“…[16][17][18][19][20][21] Besides the biological applications, the fluorescent properties of these heterocycles have received great attention in the last decade. 22,23 Due to their immense biological and photophysical importance, researchers have developed a large number of protocols [24][25][26][27][28][29][30][31] for the synthesis of such compounds, though each method has its own advantages as well as disadvantages. When the five-membered ring of diversely substituted pyrrolo[2,1-a]isoquinoline rings is fused to 2H/4H-chromen-2/4-one rings (Fig.…”

Metal-free photoinduced alkylative [3 + 2] annulation of terminal alkynes with N-alkyl isoquinolin-2-iums by catalytic isoquinoline-based electron donor–acceptor complex

“…1 a – i As such, there is growing demand to develop efficient methods for straightforward construction of the pyrrolo[2,1- a ]isoquinoline scaffold. 2–6 Conventional methodologies generally involve two different modes of reactivity as the final step, including construction of a pyrrole framework on the existing isoquinoline ring 2–5 or assembly of an isoquinoline unit on the existing pyrrole ring. 6 Typically, approaches for construction of a pyrrole framework on the existing isoquinoline ring have been proven to be powerful and popular, and are focused on cycloaddition reactions with activated unsaturated hydrocarbons (such as alkynes, alkenes and allenes), including 1,3-dipolar cycloaddition reactions, electrocyclization, Michael/condensation reactions, Michael/substitution reactions, Michael/oxidative C–N coupling reactions and N -ylide-based annulation reactions.…”

“…2–6 Conventional methodologies generally involve two different modes of reactivity as the final step, including construction of a pyrrole framework on the existing isoquinoline ring 2–5 or assembly of an isoquinoline unit on the existing pyrrole ring. 6 Typically, approaches for construction of a pyrrole framework on the existing isoquinoline ring have been proven to be powerful and popular, and are focused on cycloaddition reactions with activated unsaturated hydrocarbons (such as alkynes, alkenes and allenes), including 1,3-dipolar cycloaddition reactions, electrocyclization, Michael/condensation reactions, Michael/substitution reactions, Michael/oxidative C–N coupling reactions and N -ylide-based annulation reactions. 2–5 These cycloaddition transformations often first require the conversion of isoquinolines and their derivatives into highly reactive isoquinolinium salts (ylides), 3,4 which thus enable cycloaddition with the activated unsaturated hydrocarbons to assemble pyrrolo[2,1- a ]isoquinoline frameworks.…”