Ruthenium-catalyzed ortho-selective C-H alkenylation of aromatic compounds with alkenyl esters and ethers

Yohei Ogiwara, Masaru Tamura, Takuya Kochi, Yusuke Matsuura, Naoto Chatani, Fumitoshi Kakiuchi

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Abstract

A direct, regioselective alkenylation of aromatic C-H 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 β-styryl acetate suggested that the C-H alkenylation proceeded via a ruthenium-alkene intermediate and the C-O bond of the alkenyl acetate was cleaved by β-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-H bonds with C-O bonds of ethers was also developed.

Original languageEnglish
Pages (from-to)402-420
Number of pages19
JournalOrganometallics
Volume33
Issue number1
DOIs
Publication statusPublished - 2014 Jan 13

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ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Organic Chemistry
  • Inorganic Chemistry

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