Ⅰ. INTRODUCTIONThe intramolecular C—H insertion of cyclic carbene is a short and valuable synthetic route for highly strained small-and poly-ring compounds. However, the reaction mechanism is not clear. Jones consid...Ⅰ. INTRODUCTIONThe intramolecular C—H insertion of cyclic carbene is a short and valuable synthetic route for highly strained small-and poly-ring compounds. However, the reaction mechanism is not clear. Jones considered that n-approach mechanism is attainable, whereas an end-on approach is sterically impossible. The MINDO/3 calculations by Dewar and Chiu respectively showed that the reaction of bicyclobutanylidene 1 produced展开更多
The isomerizations and decompositions of carbenoids H<sub>2</sub>C=CLiCl and H<sub>2</sub>CLiCl have been studied by use of HF/STO-3G gradient method. Three equilibrium structures of H<sub&g...The isomerizations and decompositions of carbenoids H<sub>2</sub>C=CLiCl and H<sub>2</sub>CLiCl have been studied by use of HF/STO-3G gradient method. Three equilibrium structures of H<sub>2</sub>C=CLiCl were obtained, in which the linear structure has the lowest energy and the askew substituted structure was the next. It is found that the decomposition of H<sub>2</sub>C=CLiCl undergoes a concerted FBW rearrangement and the inversion barrier of its askew substituted structure is 36 kJ/mol. For H<sub>2</sub>CLiCl, the askew substituted structure, extending all valences of the carbon into a single hemisphere, is the lowest energy and its inversion barrier is 87 kJ/mol. The discussions on the factors concerned with the structural stabilities are given in this paper.展开更多
基金Project supported by the National Natural Science Foundation of China
文摘Ⅰ. INTRODUCTIONThe intramolecular C—H insertion of cyclic carbene is a short and valuable synthetic route for highly strained small-and poly-ring compounds. However, the reaction mechanism is not clear. Jones considered that n-approach mechanism is attainable, whereas an end-on approach is sterically impossible. The MINDO/3 calculations by Dewar and Chiu respectively showed that the reaction of bicyclobutanylidene 1 produced
文摘The isomerizations and decompositions of carbenoids H<sub>2</sub>C=CLiCl and H<sub>2</sub>CLiCl have been studied by use of HF/STO-3G gradient method. Three equilibrium structures of H<sub>2</sub>C=CLiCl were obtained, in which the linear structure has the lowest energy and the askew substituted structure was the next. It is found that the decomposition of H<sub>2</sub>C=CLiCl undergoes a concerted FBW rearrangement and the inversion barrier of its askew substituted structure is 36 kJ/mol. For H<sub>2</sub>CLiCl, the askew substituted structure, extending all valences of the carbon into a single hemisphere, is the lowest energy and its inversion barrier is 87 kJ/mol. The discussions on the factors concerned with the structural stabilities are given in this paper.
