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Quantum‐chemical models of KOH(KOBu t )/DMSO superbasic systems and mechanisms of base‐promoted acetylene reactions
Author(s) -
Vitkovskaya Nadezhda M.,
Orel Vladimir B.,
Kobychev Vladimir B.,
Bobkov Alexander S.,
Absalyamov Damir Z.,
Trofimov Boris A.
Publication year - 2020
Publication title -
international journal of quantum chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.484
H-Index - 105
eISSN - 1097-461X
pISSN - 0020-7608
DOI - 10.1002/qua.26158
Subject(s) - superbase , carbanion , chemistry , acetylene , nucleophile , triple bond , reagent , nucleophilic addition , base (topology) , dimethyl sulfoxide , furan , medicinal chemistry , computational chemistry , organic chemistry , combinatorial chemistry , catalysis , double bond , mathematical analysis , mathematics
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(OBu t )/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 (KOBu t ·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.