亚胺离子
吡咯烷
化学
亲核细胞
催化作用
离子
加合物
药物化学
有机催化
共轭体系
计算化学
有机化学
对映选择合成
聚合物
作者
Anna M. Costa,Víctor Cascales,Alejandro Castro‐Alvarez,Jaume Vilarrasa
出处
期刊:ACS omega
[American Chemical Society]
日期:2022-05-26
卷期号:7 (22): 18247-18258
标识
DOI:10.1021/acsomega.1c07020
摘要
The tendency of carbonyl compounds to form iminium ions by reaction with pyrrolidine or chiral pyrrolidine derivatives (in other words, the relative stability to hydrolysis of these iminium ions) has been computationally examined, mainly using the M06-2X/6-311+G(d,p) method. We have thus obtained the equilibrium positions for R-CH=O + CH2=CH-CH=N+R2* → R-CH=N+R2* + CH2=CH-CH=O reactions and for related exchanges. In these exchanges, there is a transfer of a secondary amine between two carbonyl compounds. Their relative energies may be used to predict which iminium species can be predominantly formed when two or more carbonyl groups are present in a reaction medium. In the catalytic Michael additions of nucleophiles to iminium ions arising from conjugated enals, dienals, and trienals, if the formation of the new Nu-C bond is favorable, the chances of amino-catalyzed reactions to efficiently proceed, with high conversions, depend on the calculated energy values for these exchange equilibria, where the iminium tetrafluoroborates of the adducts (final iminium intermediates) must be more prone to hydrolysis than the initial iminium tetrafluoroborates. The density functional theory (DFT) calculations indicate that the MacMillan catalysts and related oxazolidinones are especially suitable in this regard.
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