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Quantum‐chemical models of KOH(KOBut)/DMSO superbasic systems and mechanisms of base‐promoted acetylene reactions
International Journal of Quantum Chemistry ( IF 2.3 ) Pub Date : 2020-01-24 , DOI: 10.1002/qua.26158
Nadezhda M. Vitkovskaya 1 , Vladimir B. Orel 1 , Vladimir B. Kobychev 1 , Alexander S. Bobkov 1 , Damir Z. Absalyamov 1 , Boris A. Trofimov 2
Affiliation  

The mechanisms of fundamental base‐promoted acetylene reactions, namely, nucleophilic addition to the triple C ≡ C bond (vinylation) and nucleophilic addition of acetylenic carbanion to a carbonyl group (ethynylation), are addressed using three models of different complexity—pentasolvate, monosolvate, and anionic—which describe the catalytic superbasic systems MOH(OBut)/DMSO (suspensions of alkali hydroxides or tert‐butoxides in dimethyl sulfoxide). The above acetylene reactions and sequential transformations of reagents arranged by the superbasic center are modeled within the framework of the most complete pentasolvate model, in which the superbase is represented by the KOH·5DMSO (KOBut·5DMSO) complexes. We have developed approaches to the construction of simplified models (monosolvate and anionic) to describe transformations in complex systems. The mechanisms of cascade assemblies of 6,8‐dioxabicyclo[3.2.1]octanes, cyclopentenones, and furan cycles from ketones and acetylenes in the superbasic environment are investigated using a uniform B2PLYP/6‐311+G**//B3LYP/6‐31+G* approach, and the energy profiles of these different carbo‐ and heterocycles are analyzed.

中文翻译:

KOH(KOBut)/ DMSO超碱体系的量子化学模型及碱助炔反应的机理

基本的碱促进乙炔反应的机制,即亲核加成至三键C≡C键(乙烯基化)和亲核加成炔属碳负离子加成羰基(乙炔基),使用三种不同复杂度的模型进行了研究—五溶剂合物,单溶剂合物,和阴离子-描述催化超碱体系MOH(OBu t)/ DMSO(碱金属氢氧化物或丁醇在二甲亚砜中的悬浮液)。以上乙炔反应和由超碱性中心排列的试剂的顺序转化是在最完整的五溶剂合物模型的框架内建模的,其中超碱由KOH·5DMSO(KOBu t·5DMSO)配合物。我们已经开发出用于构造简化模型(单溶剂化物和阴离子模型)的方法,以描述复杂系统中的转化。使用均匀的B2PLYP / 6-311 + G ** // B3LYP / 6,研究了在超碱性环境中6,8-二氧杂双环[3.2.1]辛烷,环戊烯酮和呋喃环酮和乙炔的级联组装机理。 ‐31 + G *方法,并分析了这些不同的碳环和杂环的能量分布。
更新日期:2020-03-16
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