Preparation of 1, 2, 5‐Trisubstituted 1H‐Imidazoles from Ketenimines and Prop­arg­ylic Amines by Silver‐Catalyzed or Iodine‐Promoted Electrophilic Cyclization Reaction of Alkynes. Issue 26 (6th August 2015)

• Record Type: Journal Article
• Authors: Zhou, Xiaorong; Jiang, Zheng; Xue, Lexing; Lu, Ping; Wang, Yanguang
• Is Part Of: European journal of organic chemistry. Issue 26(2015)
• Page Start: 5789
• Page End: 5797
• Publication Date: 2015-08-06
• Subjects: Synthetic methods -- Domino reactions -- Cyclization -- Nitrogen heterocycles -- Ketenimine; Chemistry, Organic -- Periodicals; Organic compounds -- Synthesis -- Periodicals; Bioorganic chemistry -- Periodicals; Chemistry, Physical organic -- Periodicals; 547
• DOI: 10.1002/ejoc.201500704
• Languages: English
• ISSNs: 1434-193X

Abstract

Abstract: From readily available propargylic amines, 1, 2, 5‐trisubstituted imidazoles are efficiently obtained through a cascade reaction catalyzed by AgOTf or promoted by molecular iodine. The AgOTf‐catalyzed reaction involves nucleophilic addition of propargylic amine to ketenimine, a silver‐catalyzed electrophilic cyclization reaction of alkyne, and a tautomerism/isomerism/metal‐H exchange cascade. The iodine‐mediated counterpart yields 5‐formyl‐1, 2‐disubtituted imidazoles, which presumably includes a cascade hydrolysis/oxidation reaction. Furthermore, the presented protocol can be scaled up and the resultant 1, 2, 5‐trisubstituted imidazole can be converted into fused indeno[1, 2‐ d ]imidazole. Abstract : 1, 2, 5‐Trisubstituted imidazoles are efficiently prepared from readily available propargylic amines through a AgOTf‐catalyzed or molecular iodine‐promoted cascade reaction. The presented protocol can be scaled up and the resultant 1, 2, 5‐trisubstituted imidazoles can be converted into fused indeno[1, 2‐ d ]imidazoles.