Predicting the origin of selectivity in NHC-catalyzed ring opening of formylcyclopropane: a theoretical investigation

Abstract

Using density functional theory, we investigated the origin of selectivity in the N-heterocyclic carbene (NHC)-catalyzed transformation of formylcyclopropane with an alkylidene oxindole.

Mechanisms and Stereoselectivities in the NHC-Catalyzed [4 + 2] Annulation of 2-Bromoenal and 6-Methyluracil-5-carbaldehyde

“…To disclose the origin of chemoselectivity, we conducted Parr function analysis, which has been successfully used to characterize the electrophilic and nucleophilic centers of a molecule as well as to explain the regio- and chemoselectivities of a reaction . As listed in Table , the electrophilic P k + Parr function of the C6 atom in E -M4 is 0.34, which is larger than those of C2 (0.22) and C5 (−0.07).…”

A Computational Study on Cycloaddition Reactions between Isatin Azomethine Imine and in situ Generated Azaoxyallyl Cation

“…In order to obtain more reliable free‐energy data, single‐point energy calculations were performed using the larger 6‐311++G(2d,2p) basis set for all elements. The m06 method has been widely used in both geometrical optimizations and single‐point calculations, in order to consider the dispersion effect [38–40] . The contributions of small vibrational frequencies to entropies were corrected on the basis of Grimme's quasi‐RRHO approach, [41] with the use of Lu's Shermo program [42] .…”

DFT investigation of the DDQ-catalytic mechanism for constructing C–O bonds

“…All the calculations were accomplished using the Gaussian 09 suite of program. 24 The structures for reactants, intermediates, transition states and products were calculated at the level of M06-2X-D3/ma-def2-SVP [25][26][27][28][29][30] in the SMD solvent model, 31 which has been proved to be a powerful method to obtain accurate results in the process of investigating the mechanisms of organic chemistry. 4,14,15,[31][32][33][34][35][36][37][38][39][40][41] The vibration analysis shows no imaginary frequency, indicating that the corresponding structure is located at the minimum position on its potential energy surface, and the stability of the optimized compound is established.…”