Synthesis of dihydroquinoxaline-2(1H)-ones via palladium-catalyzed intramolecular C–N bond formation. Issue 29 (20th July 2016)

• Record Type: Journal Article
• Authors: Areephong, Jetsuda; Huo, Bright; Mbaezue, Ifenna I.; Ylijoki, Kai E.O.
• Is Part Of: Tetrahedron letters. Volume 57:Issue 29(2016)
• Page Start: 3124
• Page End: 3126
• Publication Date: 2016-07-20
• Subjects: Palladium catalysis -- Cyclization -- C–N bond formation -- Dihydroquinoxaline-2(1H)-ones; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tetlet.2016.06.008
• Languages: English
• ISSNs: 0040-4039

Abstract

Graphical abstract: Highlights: Pd-catalyzed C–N coupling for heterocycle preparation. NaI-catalyzed SN 2 substitution with alkyl and aryl amine nucleophiles. Divergent synthesis of aminoalcohols. Highly-substituted dihydroquinoxaline-2(1 H )-one synthesis. Abstract: A new strategy for the preparation of highly-substituted dihydroquinoxaline-2(1 H )-ones is reported. The strategy harnesses a divergent NaI-catalyzed amine substitution of mesylates to prepare a range of sterically hindered amidoamine substrates. These substrates are then subjected to Pd(dba)2 /P( t Bu)3 mediated cyclization. The preparation of amidoalcohol substrates occurs with reasonable yields (40–84%), with lower yields being obtained with aromatic and bulky amines. Palladium-catalyzed intramolecular C–N bond formation is slow, requiring 10 mol % catalyst loadings for complete conversion in 16 h. All substrates cyclized with reasonable yields (48–73%).