A density functional theory study on lewis acid‐catalyzed transesterification of β‐oxodithioesters

Abstract

The detailed mechanisms of the Lewis acid-catalyzed transesterification of b-oxodithioesters at a solvent-free condition were studied using density functional theory. Five possible reaction pathways, including one noncatalyzed (channel 1) and four Lewis acid-catalyzed channels (SnCl 2 -catalyzed channels 2 and 3 and SnCl 2 Á2H 2 O-catalyzed channels 4 and 5), were investigated. Our calculated results indicate that the energy barriers of the catalyzed channels are significantly lower than that of channel 1. Channel 5, which has an energy barrier of 33.70 kcal/mol as calculated at the B3LYP/ [6-31G(d, p)1LANL2DZ] level, is the most energy-favorable channel. Moreover, one water molecule of SnCl 2 Á2H 2 O par-ticipated in the transesterification in channel 5. Thus, we report a novel function of the SnCl 2 Á2H 2 O catalyst, which is quite different from the function of the conventional nonhydrated Lewis acid SnCl 2 . To understand the function of these two Lewis acid catalysts better, the global reactivity indexes and natural bond orbital charge were analyzed. This work helps in understanding the function of the Lewis acid in transesterification, and it can provide valuable insight for the rational design of new Lewis acid catalysts.

Reactions of Ethynyloxy Radical with Hydroperoxyl Radical: Bridging Theoretical Reaction Dynamics and Chemical Modeling of Combustion

“…To show the overall different performances of the Minwegen model and updated model more specifically, statistical error analysis is carried out by calculating the mean signed errors (MSE), the mean unsigned errors (MUE), the maximum absolute deviation ($${\left|{\Phi }_{{\rm m}{\rm a}{\rm x}}\right|}$$ ), the 2×population standard deviation (2σ MSE ) and 2×root‐mean‐square deviations (2RMSD) between kinetic modeling results and experimental measurements. The calculation methold [37] and result can be found in the Supporting Information. The statistical error analysis results, depicted in Figure S5, demonstrate that the updated model exhibits improved performance in predicting the concentration variation of ketene oxidation.…”

Refining the thermochemical properties of CF, SiF, and their cations by combining photoelectron spectroscopy, quantum chemical calculations, and the Active Thermochemical Tables approach

“…In fact, while in the case of CF and CF + the situation is relatively benign, there being available thermochemical values for CF that arguably appear reliable, things are veritably more complicated in the case of SiF and SiF + . Namely, the values for the enthalpy of formation of SiF available from the literature 24,25,29,69,71,[77][78][79][80][81][82][83][84][85][86][87][88] encompass a spectacularly wide range, differing on the extremes by more than 16 kcal mol À1 , Fig. 6 Energies of the lowest vibrational levels of the electronic ground state of SiF + with respect to its v + = 0 level as a function of…”

Theoretical investigation toward organophosphine‐catalyzed [3 + 3] annulation of Morita–Baylis–Hillman carbonates with azomethine imines: Mechanism, origin of stereoselectivity, and role of catalyst

“…Over the past several decades, DFT has been demonstrated to be a powerful method for studying the detailed reaction mechanisms and predicting the stereoselectivities as well as chemoselectivities in organic, biological, and transition‐metal‐catalyzed reactions . Phosphine‐catalyzed reactions have also attracted much attention from theoretical chemists because of their special reactivities and broad applications.…”