Can steric hindrance cause a gradual change in the ring-closure mechanism of complexes of the type W(CO)5N-N, where N-N represents a series of substituted bipyridine ligands?

1994 ◽  
Vol 13 (1) ◽  
pp. 91-93 ◽  
Author(s):  
Shibai Cao ◽  
Kedika Bal Reddy ◽  
Edward M. Eyring ◽  
Rudi van Eldik
Keyword(s):  
Steric Hindrance ◽  
Ring Closure ◽  
Gradual Change ◽  
Closure Mechanism

Conversion of a thiohydantoin to the corresponding hydantoin via a ring-opening/ring closure mechanism

1996 ◽  
Vol 37 (43) ◽  
pp. 7727-7730 ◽  
Author(s):  
François Goubet ◽  
Georges Teutsch
Keyword(s):  
Ring Opening ◽  
Ring Closure ◽  
Closure Mechanism

Barrierless Reactions of Three Benzonitrile Radical Cations with Ethylene

2020 ◽  
Vol 73 (8) ◽  
pp. 705
Author(s):  
Oisin J. Shiels ◽  
P. D. Kelly ◽  
Stephen J. Blanksby ◽  
Gabriel da Silva ◽  
Adam J. Trevitt
Keyword(s):  
Ion Trap ◽  
Radical Cations ◽  
Branching Ratios ◽  
Ring Closure ◽  
Van Der Waals Complexes ◽  
Rate Coefficients ◽  
Ion Trap Mass Spectrometry ◽  
Closure Mechanism ◽  
Product Ions ◽  
Product Branching

Reactions of three protonated benzonitrile radical cations with ethylene are investigated. Product branching ratios and reaction kinetics, measured using ion-trap mass spectrometry, are reported and mechanisms are developed with support from quantum chemical calculations. Reactions proceed via pre-reactive van der Waals complexes with no energy barrier (above the reactant energy) and form radical addition and addition–elimination product ions. Rate coefficients are 4-dehydrobenzonitrilium: 1.72±0.01×10−11 cm3 molecule−1 s−1, 3-dehydrobenzonitrilium: 1.85±0.01×10−11 cm3 molecule−1 s−1, and 2-dehydrobenzonitrilium: 5.96±0.06×10−11 cm3 molecule−1 s−1 (with±50% absolute uncertainty). A ring-closure mechanism involving the protonated nitrile substituent is proposed for the 2-dehydrobenzonitrilium case and suggests favourable formation of the protonated indenimine cation.

The ring-closure mechanism for aracylamides of arylcarboxylic acids

1966 ◽  
Vol 1 (3) ◽  
pp. 263-265
Author(s):  
N. P. Demchenko
Keyword(s):  
Ring Closure ◽  
Closure Mechanism

Radical-Carbanion Cyclo-Coupling in Armed Aromatics: Overriding Steric Hindrance to Ring Closure.

ChemInform ◽  
2006 ◽  
Vol 37 (4) ◽  
Author(s):  
Mark D. Roydhouse ◽  
John C. Walton
Keyword(s):  
Steric Hindrance ◽  
Ring Closure

Steric acceleration of a ring closure to an oxazepinone by steric hindrance

1971 ◽  
Vol 8 (1) ◽  
pp. 149-151 ◽  
Author(s):  
Jonathan Turk ◽  
William M. Haney ◽  
Georgia Heid ◽  
Richard E. Barlow ◽  
Leallyn B. Clapp
Keyword(s):  
Steric Hindrance ◽  
Ring Closure

Formation of lactones via a radical ring closure mechanism

1986 ◽  
pp. 85 ◽  
Author(s):  
Athelstan L. J. Beckwith ◽  
Paul E. Pigou
Keyword(s):  
Ring Closure ◽  
Radical Ring ◽  
Closure Mechanism

Cyclopropanation of styrenes and stilbenes using lithiomethyl trimethylammonium triflate as methylene donor

2014 ◽  
Vol 50 (73) ◽  
pp. 10608-10610 ◽  
Author(s):  
Juan M. Sarria Toro ◽  
Tim den Hartog ◽  
Peter Chen
Keyword(s):  
Ring Closure ◽  
Closure Mechanism

Soluble lithiomethyl trimethylammonium triflate can cyclopropanate styrenes and stilbenes efficiently. Kinetic experiments support a carbolithiation-ring closure mechanism.

Spectroscopic Investigations of the Photochemical Ring-closure Mechanism of Stilbene Type Hydrocarbons in Solution

1976 ◽  
Vol 101 (1-6) ◽  
pp. 1-10 ◽  
Author(s):  
Th. Kindt ◽  
E.-P. Resewitz ◽  
Ch. Goedicke ◽  
E. Lippert
Keyword(s):  
Ring Closure ◽  
Spectroscopic Investigations ◽  
Closure Mechanism

scholarly journals Inhibiting the Dealkylation of Basic Arenes during n-Alkane Direct Aromatization Reactions and Understanding the C6 Ring Closure Mechanism

ACS Catalysis ◽  
2020 ◽  
Vol 10 (15) ◽  
pp. 8428-8443
Author(s):  
Jack S. Jarvis ◽  
Jonathan H. Harrhy ◽  
Aiguo Wang ◽  
Takudzwa Bere ◽  
David J. Morgan ◽  
...  
Keyword(s):  
Ring Closure ◽  
Closure Mechanism ◽  
Direct Aromatization
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