Mechanism of the cyclization of dimethyl diethynyl silane with selenium tetrabromide: Computational and structural studies, and monitoring

详细信息	查看全文 | 推荐本文 |

• 作者：Svetlana V. Amosova ; Vladimir A. Shagun ; Alex ; er V. Martynov ; Natalia A. Makhaeva ; Lyudmila I. Larina ; Konstantin A. Lysenko ; Mikhail G. Voronkov
• 关键词：Chalcogens ; Five-membered unsaturated heterocycles ; Reaction mechanisms ; NMR spectroscopy ; X-ray diffraction
• 刊名：Journal of Organometallic Chemistry
• 出版年：2007
• 期刊代码：64_0022328x
• 类别：ch
• 出版时间：15 July 2007
• 卷：692
• 期：16
• 页码：3307-3315
• 文件大小：530 K

摘要

The structure of 2,4-dibromo-2-dibromomethyl-3,3-dimethyl-1-selena-3-silacyclopentene-4, formed by regioselective electrophilic addition of SeBr₄ to dimethyl diethynyl silane, has been determined using X-ray analysis technique. Quantum chemistry methods were used to study elementary stages of the reaction. It was found that the first stage consisted of SeBr₄ conversion into bimolecular complex Br₂SeBr₂, initiated by dimethyl diethynyl silane. Possible formation of five-membered and six-membered heterocycles involves different cyclization mechanisms. The formation of only five-membered heterocycle is explained by kinetically preferable ring closure through four-center transition state. The conclusions obtained by calculations were confirmed by monitoring of the reaction using ¹H NMR method.