Golden Carousel in Catalysis: The Cationic Gold/Propargylic Ester Cycle

✍ Scribed by Andrea Correa; Nicolas Marion; Louis Fensterbank; Max Malacria; Steven P. Nolan; Luigi Cavallo

• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 374 KB
• Volume: 120
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/ange.200703769

✦ Synopsis

Gold-mediated homogeneous catalysis is rapidly growing in popularity, with a variety of applications described in recent reviews. [1] Alkynes are among the most versatile substrates, and the potential of easily accessible propargylic esters is currently being investigated by several groups. [2] However, this chemistry is still in its infancy, and results are often surprising and in some cases difficult to explain. It is known that under Au catalysis, gold propargylic esters species such as 1 undergo 1,2-and 1,3-acyl migration, [3][4][5][6] leading to the formation of gold vinyl carbenoid species such as 2 and gold allene species such as 3 (Scheme 1). Of course, the Auactivated species 1-3 are the starting points for further reactions, leading to a great diversity of products. [7] Unfortunately, the thermodynamics and the sequence of reactions connecting the three key intermediates are not yet clear, and theoretical studies related to this topic are scarce. [4e, 8-9] In this communication we propose, on the basis of DFT calculations,