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[摘要]：In this review, the regioselectivity of transition-metal-catalyzed ring cleavage of cyclopropanes and cyclobutanes by beta-carbon elimination is analyzed using experimental results and rationalization models from the literature. Most models proposed are generally consistent with the following trends: Cleavage of the less substituted bond of the small cycloalkane is favored by a minimization of steric hindrance, whereas cleavage of the more substituted bond becomes possible if steric hindrance is limited and if the substituent is electron-withdrawing or if it can coordinate the metal. Importantly, steric congestion can easily offset electronic activation. Moreover, regioselectivity models appear to be more generally applicable to cyclopropanes than to cyclobutanes. |
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