Ruthenium(II)-Catalyzed Isomer-Selective Cyclization of 1,6-Dienes Leading to exo-Methylenecyclopentanes: Unprecedented Cycloisomerization Mechanism Involving Ruthenacyclopentane(hydrido) Intermediate

Yoshihiko Yamamoto, Yu-ichiro Nakagai, Naoki Ohkoshi and Kenji Itoh*

*Department of Molecular Design and Engineering, and Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa, Nagoya 464-8603, Japan

Y. Yamamoto, Y.-i. Nakagai, N. Ohkoshi, K. Itoh, J. Am. Chem. Soc., 2001, 123, 6372-6380.

DOI: 10.1021/ja010134s

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Abstract

Ruthenium(II) complexes catalyze an efficient conversion of 1,6-dienes into the corresponding exo-methylenecyclopentanes in very good yields with good isomer purity in i-PrOH at 90 °C. In contrast, a Ru(0) complex, (C₆Me₆)Ru(cod), catalyzed the cycloisomerization only in 1,2-dichloroethane.

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proposed mechanism

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Key Words

cyclopentanes

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ID: J48-Y2001