Bifunctional Phosphine Ligand Enabled Gold‐Catalyzed Alkynamide Cycloisomerization: Access to Electron‐Rich 2‐Aminofurans and Their Diels–Alder Adducts. Issue 48 (15th October 2019)

• Record Type: Journal Article
• Authors: Li, Xingguang; Ma, Xu; Wang, Zhixun; Liu, Pei‐Nian; Zhang, Liming
• Is Part Of: Angewandte Chemie international edition. Volume 58:Issue 48(2019)
• Page Start: 17180
• Page End: 17184
• Publication Date: 2019-10-15
• Subjects: dienes -- Diels–Alder reactions -- gold -- heterocycles -- isomerizations; Chemistry -- Periodicals; 540
• DOI: 10.1002/anie.201908598
• Languages: English
• ISSNs: 1433-7851

Abstract

Abstract: By using biphenyl‐2‐ylphosphines functionalized with a remote tertiary amino group as a ligand, readily available acetylenic amides are directly converted into 2‐aminofurans devoid of any electron‐withdrawing and hence deactivating/stabilizing substituents. These highly electron‐rich furans have rarely been prepared, let alone applied in synthesis, because of their high reactivities and low stabilities associated with the electron‐rich nature of the furan ring. In this work, these reactive furans smoothly undergo either in situ intermolecular Diels–Alder reactions to deliver highly functionalized/substituted aniline products or intramolecular ones to furnish carbazole‐4‐carboxylates in mostly good to excellent yields. This work offers general and expedient access to this class of little studies electron‐rich furans and should lead to exciting opportunities for their applications. Abstract : What a ligand ! With bifunctional ligands specifically designed for gold catalysis, acetylenic amides are efficiently transformed into 2‐aminofurans in a single step. The highly electron‐rich nature of these furans makes them difficult to access by other means, but also endows them with exceptional synthetic value. D‐A=Diels–Alder, EWG=electron‐withdrawing group.