Ruthenium-Catalyzed Ortho-Selective C–H Alkenylation of Aromatic Compounds with Alkenyl Esters and Ethers

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• 作者：Yohei Ogiwara ; Masaru Tamura ; Takuya Kochi ; Yusuke Matsuura ; Naoto Chatani ; Fumitoshi Kakiuchi
• 刊名：Organometallics
• 出版年：2014
• 出版时间：January 13, 2014
• 年：2014
• 卷：33
• 期：1
• 页码：402-420
• 全文大小：958K
• ISSN：1520-6041

文摘

A direct, regioselective alkenylation of aromatic C鈥揌 bonds of aryl- and heteroarylpyridines and related compounds with alkenyl esters was developed using Ru(cod)(cot) as a catalyst. Aromatic compounds bearing electronically diverse substituents and various heterocyclic directing groups are reacted with alkenyl acetates bearing mono- and disubstituted alkenyl groups with aliphatic and aromatic substituents to give ortho-alkenylation products in high yields. The results of deuterium-labeling experiments and competition reactions using different ratios of the E and Z isomers of 尾-styryl acetate suggested that the C鈥揌 alkenylation proceeded via a ruthenium鈥揳lkene intermediate and the C鈥揙 bond of the alkenyl acetate was cleaved by 尾-acetoxy elimination. Two types of catalytically relevant species were identified, and the reactivities of these species, combined with the results of the kinetic studies, suggest that the rate-limiting step is the exchange of the COD ligand with the alkenyl ester. On the basis of the elucidated mechanism, the first catalytic coupling reaction using aromatic C鈥揌 bonds with C鈥揙 bonds of ethers was also developed.