Oxidative Heterocyclization of 2-Alkynylbenzaldehydes with 1,2-Phenylenediamine

✍ Scribed by Gerald Dyker; Wolfgang Stirner; Gerald Henkel

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 374 KB
• Volume: 2000
• Category: Article
• ISSN: 1434-193X
• DOI: 10.1002/(sici)1099-0690(200004)2000:8<1433::aid-ejoc1433>3.0.co;2-7

✦ Synopsis

quinolines (8) or isoindolo[2,1-a]quinoxalines (9) depending on the influence of additional substituents at the alkyne.

Scheme 1. Condensation of phenylenediamine 2 with bis(aldehyde) 1 under neutral and under oxidative conditions Scheme 2. Reaction conditions: a. 1 mol-% Pd(OAc) 2 , 2 mol-% PPh 3 , 1.4-2 mol-% CuI (none in case of 7.2b), Et 3 N, Ar, 80 °C, 10 h