Palladium-Catalyzed Tandem Cyclization of Bromoenynes through Aromatic CH Bond Functionalization

✍ Scribed by Hiroaki Ohno; Mio Yamamoto; Mutsumi Iuchi; Tetsuaki Tanaka

• Publisher: John Wiley and Sons
• Year: 2005
• Tongue: English
• Weight: 116 KB
• Volume: 44
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/anie.200500159

✦ Synopsis

Transition-metal-catalyzed cyclization of dienes, diynes, and enynes has received considerable attention in recent years. [1] In contrast, cyclization of this class of compounds through functionalization of a CÀH bond of an aromatic ring has scarcely been investigated. We anticipated that tandem cyclization of enynes of type 1 (Scheme 1) could serve as a useful synthetic method for direct construction of tricyclic products such as 4 through the use of a nonfunctionalized aryl group.

Recent investigations in palladium chemistry has revealed that functionalization of a CÀH bond of an aromatic group is highly effective for the construction of fused aromatic rings. [2][3][4][5][6] Although tandem cyclization involving CÀH bond functionalization that generates two, [7] three, [8] or four carbon-carbon bonds [9] in a one-pot manner and leads to