An explanation for rapid enzyme-catalyzed proton abstraction from carbon acids: importance of late transition states in concerted mechanisms

1993 ◽  
Vol 115 (24) ◽  
pp. 11552-11568 ◽  
Author(s):  
John A. Gerlt ◽  
Paul G. Gassman
Keyword(s):  
Transition States ◽  
Proton Abstraction ◽  
Carbon Acids ◽  
Late Transition

scholarly journals Assessing the effective factors affecting the conformational preferences and the early and late transition states of the unimolecular retro-ene decomposition reactions of ethyl cyanate, ethyl thiocyanate and ethyl selenocyanate

RSC Advances ◽  
2017 ◽  
Vol 7 (37) ◽  
pp. 22757-22770 ◽  
Author(s):  
Hooshang Atabaki ◽  
Davood Nori-Shargh ◽  
Mohamad Momen-Heravi
Keyword(s):  
Transition States ◽  
Factors Affecting ◽  
Effective Factors ◽  
Decomposition Reactions ◽  
Barrier Heights ◽  
Conformational Preferences ◽  
Late Transition

The variations of Δ[(HCGAE(X3–C4weakening) – HCGAE(X3–C4strengthening)] parameters correlate well with the variations of the retro-ene decomposition reactions barrier heights going from compound1to compound3.

Distinguishing the Early and Late Transition States and Exploring the Validity of σ → σ*#, σ# → σ*, and σ → π*COConcepts in Diastereoselection from NBO Analysis

2006 ◽  
Vol 71 (11) ◽  
pp. 4178-4182 ◽  
Author(s):  
Veejendra K. Yadav ◽  
Archana Gupta ◽  
Rengarajan Balamurugan ◽  
Vardhineedi Sriramurthy ◽  
Naganabonia Vijaya Kumar
Keyword(s):  
Transition States ◽  
Nbo Analysis ◽  
Late Transition

Marcus theory and the existence or non-existence of transition states in gas phase deprotonation of carbon acids

1984 ◽  
Vol 62 (8) ◽  
pp. 1465-1469 ◽  
Author(s):  
Saul Wolfe
Keyword(s):  
Proton Transfer ◽  
Gas Phase ◽  
Transition States ◽  
Marcus Theory ◽  
Energy Change ◽  
Transfer Reactions ◽  
Gas Phase Reactions ◽  
Proton Transfer Reactions ◽  
Carbon Acids ◽  
Computational Level

At the 3-21G (3-21G*) computational level, the intrinsic barriers associated with proton transfer between XCH2− and CH3X have been found to be essentially constant (ca. 10 kcal/mol) for X = H, F, SH, Cl. According to the Marcus rate-equilibrium treatment of proton transfer reactions, this result means that transition states should not exist for gas phase reactions [Formula: see text], when the energy change exceeds 20 kcal/mol. This prediction has been confirmed for two cases (X = H, F) in which the energy change is less than 20 kcal/mol, and two cases (X = SH, Cl) in which the energy change is greater than 20 kcal/mol.

New mechanistic criterion for early and late transition states

1976 ◽  
Vol 98 (24) ◽  
pp. 7819-7821 ◽  
Author(s):  
Rolf Huisgen ◽  
Reinhard Schug
Keyword(s):  
Transition States ◽  
Late Transition
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