Mechanism of Regioselective Ring-Opening Reactions of 1,2-Epoxyoctane Catalyzed by Tris(pentafluorophenyl)borane: A Combined Experimental, Density Functional Theory, and Microkinetic Study

ACS Catalysis ◽  
2018 ◽  
Vol 8 (12) ◽  
pp. 11119-11133 ◽  
Author(s):  
Ying Yu ◽  
Youlong Zhu ◽  
Mihir N. Bhagat ◽  
Arjun Raghuraman ◽  
Kurt F. Hirsekorn ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Ring Opening ◽  
Density Functional ◽  
Functional Theory ◽  
Ring Opening Reactions ◽  
Experimental Density

Mechanistic insights into the ring-opening of biomass derived lactones

RSC Advances ◽  
2016 ◽  
Vol 6 (16) ◽  
pp. 12932-12942 ◽  
Author(s):  
Shelaka Gupta ◽  
Rishabh Arora ◽  
Nishant Sinha ◽  
Md. Imteyaz Alam ◽  
M. Ali Haider
Keyword(s):  
Density Functional Theory ◽  
Ring Opening ◽  
Density Functional ◽  
Density Functional Theory Calculations ◽  
Functional Theory ◽  
Ring Opening Reactions ◽  
Oxocarbenium Ion ◽  
Acid Catalyzed

Density functional theory calculations suggest the formation of an oxocarbenium ion intermediate in acid catalyzed ring-opening reactions of biomass derived lactones, which may play an important role in determining it's reactivity.

A Density Functional Theory Study on the Ring-Opening Polymerization of D-Lactide Catalyzed by a Bifunctional-Thiourea Catalyst

2009 ◽  
Vol 62 (2) ◽  
pp. 157 ◽  
Author(s):  
Rong-Xiu Zhu ◽  
Ruo-Xi Wang ◽  
Dong-Ju Zhang ◽  
Cheng-Bu Liu
Keyword(s):  
Density Functional Theory ◽  
Ring Opening ◽  
Density Functional ◽  
Population Analysis ◽  
Density Functional Theory Calculations ◽  
Ring Opening Polymerization ◽  
Acyl Transfer ◽  
Frontier Molecular Orbital ◽  
Functional Theory ◽  
Elimination Pathway

The thiourea-catalyzed methanolysis of d-lactide, a model system for the initiation and propagation of the organocatalyzed ring-opening polymerization (ROP) of lactide, has been studied by performing density functional theory calculations. Both the catalyzed and uncatalyzed reactions are explored along two possible pathways: one involves the stepwise addition–elimination pathway and the other is related to the concerted pathway. It is found that the reaction without the presence of the catalyst is difficult because the barrier involved is as high as 176 kJ mol–1. With the aid of a thiourea catalyst, the barrier is reduced to 88 kJ mol–1 with a preference for the stepwise addition–elimination mechanism over the concerted one. The role of the catalyst has been rationalized by analyzing the frontier molecular orbital interactions between the catalyst and substrates and by performing natural population analysis. Finally, another mechanism involving acyl transfer is discussed for the thiourea-catalyzed ROP.

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

2021 ◽  
Author(s):  
Yang Wang ◽  
Yan Qiao ◽  
Yu Lan ◽  
Donghui Wei
Keyword(s):  
Density Functional Theory ◽  
Theoretical Investigation ◽  
Ring Opening ◽  
Density Functional ◽  
Functional Theory

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

Facile formation of azines from reactions of singlet methylene and dimethylcarbene with precursor diazirines: theoretical explorations

1999 ◽  
Vol 77 (5-6) ◽  
pp. 540-549 ◽  
Author(s):  
Gennady V Shustov ◽  
Michael TH Liu ◽  
K N Houk
Keyword(s):  
Density Functional Theory ◽  
Ab Initio ◽  
Ring Opening ◽  
Density Functional ◽  
Activation Barrier ◽  
Thermal Reaction ◽  
Orbital Theory ◽  
Functional Theory ◽  
Activation Barriers ◽  
Singlet Methylene

The reactions of the singlet methylene (1a) and dimethylcarbene (1b), with their diazirine precursors, diazirine (2a), and dimethyldiazirine (2b), have been studied theoretically using ab initio and density functional theory. The reaction has no activation barriers for the parent system (1a + 2a) and proceeds via a reactive complex and a transition state with a small negative enthalpy of activation Δ Hnot =298 = -1.1 kcal mol-1, ΔSnot =298 = -34.4 cal mol-1 K-1, ΔG°298 = 9.2 kcal mol-1) for the dimethyl derivatives (1b + 2b). The formation of N-methylene diazirinium ylides (3a,b) is exothermic by 64-80 kcal mol-1. The isomer, 1,3-diazabicyclo[1.1.0]butane (4a), is more stable (5-12 kcal mol-1) than isomer 3a, but can neither be formed by direct thermal reaction of 1a with 2a nor undergo the direct rearrangement into formaldazine (5a). The rearrangement of ylides 3a,b into azines 5a,b proceeds by conrotatory C3-N1 ring opening. The predicted activation barrier of ca. 15 kcal mol-1 for the ring opening in ylide 3b is in excellent agreement with experimental data. The formation of pyridinium ylides from carbenes and pyridine is also studied.Key words: diazirinium ylide, ab initio MO (molecular orbital) theory, density functional theory, pyridinium ylide, CIS (singles configuration interaction) transition energies.

scholarly journals Geometry and energy of amidoenethiolate conformers formed by ring-opening of several thiazolium ions in base: a theoretical study using density functional theory

ARKIVOC ◽  
2001 ◽  
Vol 2001 (12) ◽  
pp. 116-133 ◽  
Author(s):  
Belquis Mothana ◽  
Trevor A. Bourgeois ◽  
Rebecca M. Longley ◽  
Geri-Lynn Devereaux ◽  
Robert S. McDonald ◽  
...  
Keyword(s):  
Density Functional Theory ◽  
Ring Opening ◽  
Density Functional ◽  
Theoretical Study ◽  
Functional Theory
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