img
Computational Insight Into the Enantioselectivity of Homoboroproline Catalyzed Asymmetric Aldol Reaction    
Yazarlar
Habibe Dulger
Özlem Sarı
Kırşehir Ahi Evran Üniversitesi, Türkiye
Prof. Dr. Nadir DEMİREL Prof. Dr. Nadir DEMİREL
Kırşehir Ahi Evran Üniversitesi, Türkiye
Safiye Erdem
Marmara Üniversitesi, Türkiye
Özet
Chiral amino boronic acids and their derivatives have a wide range of applications including enzyme inhibitors, anti-cancer agents and molecular sensors. They also draw attention as effective catalysts. Recently, a new proline based amino boronic acid derivative, homoboroproline, was synthesized and demonstrated to be an efficient catalyst in an asymmetric aldol reaction. The reaction mechanism has been elucidated in the present study for the first time. Considering different orientations of the enamine intermediate and the aldehyde, potential alternative mechanisms were modeled with density functional theory (DFT) calculations via PCM/M06-2X/6-31G(d,p) method in acetone. The potential energy surface of each mechanism was explored to establish the rate-determining and enantioselectivity-determining steps. The calculated enantiomeric excess values (>99%) were found to be in agreement with the experimental values (93%, 95%). The detailed investigation of the transition state structures of the selectivity-determining step has revealed that attractive interactions between boron and aldehyde oxygen are responsible for the selectivity confirmed by natural bond orbital (NBO) analysis. The results provide insight into the origin of enantioselectivity in asymmetric aldol reaction catalyzed by homoboroproline.
Anahtar Kelimeler
Aldol reaction | Boronate ester catalyst | Density functional calculations | Enantioselectivity | Natural Bond Orbitals
Makale Türü Özgün Makale
Makale Alt Türü SSCI, AHCI, SCI, SCI-Exp dergilerinde yayımlanan tam makale
Dergi Adı ChemistrySelect
Dergi ISSN 2365-6549
Dergi Tarandığı Indeksler SCI
Dergi Grubu Q3
Makale Dili İngilizce
Basım Tarihi 07-2019
Cilt No 4
Sayı 27
Sayfalar 7959 / 7967
Doi Numarası 10.1002/slct.201901737
Makale Linki https://onlinelibrary.wiley.com/doi/abs/10.1002/slct.201901737