Metal‐Free Cyclocarboamination of ortho‐Formyl Phenylacetylenes with Secondary Amines: Access to 1,3‐Diamino‐1H‐Indenes and 3‐Amino‐1‐Indanones

• Published in: Advanced synthesis & catalysis Vol. 361; no. 3; pp. 569 - 577
• Main Authors: Cui, Jian‐Fang, Tang, Rishi, Yang, Bin, Lai, Nathanael Chun‐Him, Jiang, Jia‐Jun, Deng, Jie‐Ren, Wong, Man‐Kin
• Format: Journal Article
• Language: English
• Published: WEINHEIM Wiley 01.02.2019; Wiley Subscription Services, Inc
• Subjects: Aminal; Amine activation; Amines; Anions; Carboamination; Chemistry; Chemistry, Applied; Chemistry, Organic; Indanone; Indene; Iodine; Physical Sciences; Science & Technology; Aminal; INSERTION; ACID; Indanone; INTERNAL ALKYNES; CATALYZED HYDROAMINATION; ALKENES; Carboamination; Amine activation; Indene; HETEROCYCLES; H BONDS; GENERATION; CYCLIZATION
• ISSN: 1615-4150; 1615-4169
• DOI: 10.1002/adsc.201801318

This work first discloses a new strategy for amine activation to give reactive amine anion by in situ generated iminium cation‐amine anion pair through decomposition of sterically hindered aminals. Utilizing this strategy, a highly regio‐ and chemoselective cyclocarboamination of ortho‐formyl phenylacetylenes with secondary amines has been realized under metal‐free mild reaction conditions. The cyclocarboamination with notably tunable product profiles depends on the separation and purification procedure, a diverse range of 1, 3‐diamino‐1H‐indenes (essentially reactive enamines) and 3‐amino‐1‐indanones were obtained, respectively. Moreover, using iodine as an electrophile to couple with various ortho‐formyl phenylacetylenes and secondary amines, a series of 3‐amino‐2‐iodo‐1‐indanones were efficiently achieved with four bonds (C=O, C−C, C−N and C−I) formation in an one‐pot three‐component reaction. These results demonstrated an unprecedented methodology for the construction of highly functionalized 1H‐indene and 1‐indanone compounds.