Palladium-Catalyzed Insertion of an Allene into an Aminal: Aminomethylamination of Allenes by CN Bond Activation

• Published in: Angewandte Chemie (International ed.) Vol. 53; no. 28; pp. 7272 - 7276
• Main Authors: Hu, Jianhua, Xie, Yinjun, Huang, Hanmin
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 07.07.2014; WILEY‐VCH Verlag; Wiley
• Subjects: Activation; Alkadienes - chemistry; Allene; allenes; aminals; Amination; Bonding; Carbon - chemistry; Catalysis; Cationic; Chemistry; Chemistry, Multidisciplinary; Cleavage; Coordination Complexes - chemistry; CN activation; diamines; Formations; gamma-Aminobutyric Acid - chemistry; Insertion; Links; Methylamines - metabolism; Molecular Structure; Nitrogen - chemistry; palladium; Palladium - chemistry; Physical Sciences; Science & Technology; Synthesis; aminals; ASYMMETRIC-SYNTHESIS; ALKENE DIAMINATION; IMINES; C-N activation; COMPLEXES; AMINOACETOXYLATION; DIFUNCTIONALIZATION; allenes; ETHERS; REDUCTION; palladium; METAL; DERIVATIVES; diamines; CN activation
• ISSN: 1433-7851; 1521-3773
• DOI: 10.1002/anie.201403774

A new and atom‐economic palladium‐catalyzed aminomethylamination of allenes with aminals by CN bond activation is described. This direct and operationally simple method provides a fundamentally novel approach for the synthesis of 1,3‐diamines. Mechanistic studies suggest that a unique cationic π‐allylpalladium complex containing an aminomethyl moiety is generated as a key intermediate through the carbopalladation of the allene with a cyclometalated palladium–alkyl species. Break to link: The direct insertion of an allene into the CN bond of an aminal in the presence of a palladium catalyst is described. This new method is concise and operationally simple and can be used for the atom‐economic synthesis of a broad range of 1,3‐diamines. The reaction involves cleavage of the CN bond, formation of a π‐allylpalladium intermediate, and nucleophilic addition.