Synthesis of Isoquinolinones via Regioselective Palladium-Catalyzed C–H Activation/Annulation

Abstract

Abstract:The isoquinoline motif and its derivatives are of significant interest due to their important biological activities. The effective synthesis of substituted isoquinoline compounds has historically been a significant challenge. A new palladium-catalyzed C-H activation/annulation of N-methoxy benzamides and 2,3-allenoic acid esters is described. For the first time, 2,3-allenoic acid esters are employed for the syntheses of 3,4-substituted hydroisoquinolones, the heteroannulation of allenes proceeded smoothly and afforded the products with good yields and excellent regioselectivity.

Metallaphotoredox-catalyzed C–H activation: regio-selective annulation of allenes with benzamide

“…Allenes, bearing two orthogonal cumulative carbon-carbon double bonds, have been applied into a wide variety of annulations [18][19][20][21][22][23][24][25]. Various noble second-and third-row transition metals such as Pd [26][27][28][29][30][31][32], Ir [33], Rh [34][35][36][37][38][39][40] and Ru [41], have been employed for the preparation of cyclic scaffolds from simple, nonfunctionalized acyclic starting materials. Moreover, the rst-row transition metals, such as Mn [42][43][44][45][46][47], Fe [48], Ni [49][50][51][52][53] and Co [54][55][56][57][58][59][60][61][62][63], have been recognized as cheap, environmentally friendly and reactively effective catalysis for C − H functionalization with allenes.…”

Metallaphotoredox-Catalyzed C−H Activation: Regio-Selective Annulation of Allenes with Benzamide

“…Allenes, bearing two orthogonal cumulative carbon-carbon double bonds, have been applied into a wide variety of annulations [18][19][20][21][22][23][24][25]. Various noble second-and third-row transition metals such as Pd [26][27][28][29][30][31][32], Ir [33], Rh [34][35][36][37][38][39][40] and Ru [41], have been employed for the preparation of cyclic scaffolds from simple, nonfunctionalized acyclic starting materials. Moreover, the rst-row transition metals, such as Mn [42][43][44][45][46][47], Fe [48], Ni [49][50][51][52][53] and Co [54][55][56][57][58][59][60][61][62][63], have been recognized as cheap, environmentally friendly and reactively effective catalysis for C − H functionalization with allenes.…”

Introduction of Diverse Functional Groups to Isoquinolines by Microwave‐assisted Transition Metal‐catalyzed Coupling Reactions

“…Although these electrophilic cyclizations have merit due to their ease of preparation concerning the isoquinoline core, previously fixed substituents of isoquinolines create limitations for further functional group modification. Recently, transition metal‐catalyzed direct CH function/annulation was established for constructing valuable isoquinoline derivatives . This synthetic method provided C3‐ and C4‐aromatic‐substituted isoquinolines with internal or terminal alkynes; however, any further functionalization of the isoquinoline for molecular diversity was significantly limited.…”