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Abstract: In order to explore the new and efficient cyclopropanation reagents, a theoretical investigation of the cyclopropanation reactions of aluminum carbenoid Cl2AlCH2Cl with olefins was given at the B3LYP level of theory. All of the reactions examined displayed similar concerted mechanisms for the cyclopropanation of these reagents. The reactions are predicted to be highly chemical reactivity with low barriers and could be favored in experiment, and the cyclopropanation reaction proceed easily at lower temperature. The computational results are briefly compared to other carbenoid reactions and related species. [Copyright &y& Elsevier]

Abstract: In order to explore the new and efficient cyclopropanation reagents, a theoretical investigation of the cyclopropanation reactions of titanium carbenoid PhOTiCl2CH2Cl and Cl3TiCH2Cl with olefins was given at the B3LYP level of theory. All of the reactions examined displayed similar concerted mechanisms for the cyclopropanation of these reagents. The reactions are predicted to be highly chemical reactivity with low barriers and could be favored in experiment, and the cyclopropanation reaction proceed easily at lower temperature. The computational results are briefly compared to other carbenoid reactions and related species. [Copyright &y& Elsevier]

Abstract: The mechanisms for the abstraction reactions of germylenes with oxirane and thiirane have been characterized in detail using density functional theory. All the stationary points were determined at the B3LYP/6-311++G (d, p) level of the theory. As a result, our theoretical investigations suggest that, irrespective of deoxygenation and desulfurization, the alkyl-substituted germylene abstractions are much more favorable than those of the π-donor-substituted germylenes. Moreover, for a given germylene, the desulfurization reaction is more exothermic as well as more kinetically favorable. Furthermore, a configuration mixing model based on the work of Pross and Shaik is used to rationalize the computational results. A comparison with carbene and silylene also led to the same result and the results obtained allowed a number of predictions to be made. [Copyright &y& Elsevier]