3 -Isoquinolinones amination

The direct anionic cyclization of 2-alkynylbenzonitriles 45 was applied to the synthesis of isoquinolinones <99T13193> and phenanthridines <990L767>. A bw-alkylation process of an amine with a hii-mesylate afforded the tetrahydroisoquinoline ring system <99SC645>. 

Benzopyrenes are also useful starting materials for preparing 3(2//)-isoquinolinones. Similarly, 15 and its N-substituted derivatives can be synthesized with ammonia or with amines [70JCS(C)536]. 

In 2008, Jones et cd. disclosed a stoichiometric Rh(III)-mediated reaction of JV-benzylidenemethylamine with dimethyl acetylenedicarboxylate to give the corresponding isoquinolinium salt [52a]. Inspired by this work, in 2012 we developed a Rh(III)-catalyzed one-pot synthesis of isoquinolinium salts 104 from benzaldehydes, primary amines, and internal alkynes by C-H activation and annulation [52b]. This was the first report for the synthesis of isoquinohnium salts by catalytic C-H activation. It is noteworthy that the current procedure was successfully apphed to the total synthesis of isoquinolinone alkaloid oxy-chelerythrine 105 (Eq. (5.99)). In 2013, our group and Huang independently found that various isoquinohnium salts could be synthesized from aryl ketimines, 2-phenyl pyridines, and alkynes under similar reaction conditions, as shown in Eqs. (5.100)-(5.102) [52c-e]. 

Recently, Guchhait and Madaan have reported the synthesis of N-fused imidazole-amines 380 and isoquinolinone-imidazoles 381 by employing 2-aminopyridine 6g, Izb, and various aldehydes (e.g., 9zb, 9zc) in the GBB-4C-3CR (Scheme 7.117) [125],... 

SCHEME 7.117 Synthesis of Af-fused imidaz le-amines (380) and isoquinolinone-imidazole (381) using Izb. 

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