Camphor-based О±-Bromoketones for the Asymmetric Darzens Reaction: Insights into the Mechanism Using Density Functional Theory
J.Y. Yuan1, X.C. Liao2, H.M. Wang3, M.S. Tang4
1 Center of Computational Chemistry, Department of Chemistry, Zhengzhou University, hmwang06@163.com
2 Center of Computational Chemistry, Department of Chemistry, Zhengzhou University, hmwang06@163.com
3 Center of Computational Chemistry, Department of Chemistry, Zhengzhou University, hmwang06@163.com
4 Center of Computational Chemistry, Department of Chemistry, Zhengzhou University, hmwang06@163.com
Ключевые слова: DFT, Darzens condensation, benzaldehyde, acetaldehyde, endo-2-bromoacetylisoborneol, mechanism, transition states, diastereoselectivity, aldol, boat-like, chair-like
Страницы: 851-860
Аннотация
Density functional theory (DFT) calculations at B3LYP/6-31G(d,p) level were carried out to investigate the mechanism of the reaction of benzaldehyde (BA) or acetaldehyde (AD) with (1R)-2-endo-bromoacetyl-1,7,7-trimethylbicyclo[2.2.1]heptan-2-ol (endo-2-bromoacetylisoborneol) 1 (Scheme 1). The calculations indicate that the reactions are diastereoselective, in good agreement with the experimental results [1]. Moreover, the calculations show that these reactions proceed via two steps: (1) an aldol-like reaction and (2) the formation of an epoxide. Our calculation study of the transition states demonstrate that the terminal hydroxyl group in compound 1 is vital to the stereoselectivity of the reactions.
|
