Gold-catalyzed oxidation of terminal alkynes to glyoxals and their reactions with 2-phenylimidazo[1,2-]pyridines: one-pot synthesis of 1,2-diones

• Published in: Organic & biomolecular chemistry Vol. 19; no. 4; pp. 8735 - 8739
• Main Authors: Liao, Shengrong, Xu, Huayan, Yang, Bin, Wang, Junfeng, Zhou, Xuefeng, Lin, Xiuping, Liu, Yonghong
• Format: Journal Article
• Language: English
• Published: CAMBRIDGE Royal Soc Chemistry 20.10.2021; Royal Society of Chemistry
• Subjects: Alkanes; Alkynes; Cascade chemical reactions; Chemical reactions; Chemistry; Chemistry, Organic; Gold; Ketones; Nucleotide sequence; Oxidation; Oxygenation; Physical Sciences; Pyridines; Science & Technology; Substrates; ROUTE; ZOLPIDEM; DICARBONYLATION; EFFICIENT; DERIVATIVES; IMIDAZOHETEROCYCLES
• DOI: 10.1039/d1ob01507a
• ISSN: 1477-0520

A novel one-pot protocol for the convenient and efficient synthesis of (2-phenylimidazo[1,2- a ]pyridin-3-yl)alkane-1,2-diones ( 3 ) in good yields (32-88%) from 2-phenylimidazo[1,2- a ]pyridines ( 1 ) and terminal alkynes ( 2 ) has been established with a wide range of substrate scope. A tandem reaction sequence containing gold-catalyzed double oxidations of terminal alkynes to generate glyoxals, nucleophilic addition of 2-phenylimidazo[1,2- a ]pyridines to glyoxals to yield α-hydroxyl ketones, and oxygenation of the α-hydroxyl ketones to afford the final products 3 under air atmosphere is involved in this method. Simple operation, mild reaction conditions, and widely available substrates make this strategy more affordable. A one-pot procedure with a tandem reaction sequence of oxidative gold catalysis, nucleophilic addition and oxygenation was employed to synthesize 1,2-diones from 2-phenylimidazo[1,2- a ]pyridines and terminal alkynes in good yields.