Theory of Substituent Effects on Pericyclic Reaction Rates:  Alkoxy Substituents in the Claisen Rearrangement

1997 ◽  
Vol 119 (12) ◽  
pp. 2877-2884 ◽  
Author(s):  
Hi Young Yoo ◽  
K. N. Houk
Keyword(s):  
Claisen Rearrangement ◽  
Substituent Effects ◽  
Reaction Rates ◽  
Pericyclic Reaction

The Thermal Decomposition of N-Arylcarbamates of t-Alcohols. 2. Effects of Solvent, Temperature, and Substituents

1972 ◽  
Vol 50 (21) ◽  
pp. 3478-3487 ◽  
Author(s):  
S. J. Ashcroft ◽  
Melanie P. Thorne
Keyword(s):  
Diphenyl Ether ◽  
Substituent Effects ◽  
Reaction Rates ◽  
Specific Rate ◽  
Cyclic Transition ◽  
Tertiary Alcohols ◽  
Carbonium Ion ◽  
Tertiary Carbon ◽  
Cyclic Transition State ◽  
Influence Of Solvent

The influence of solvent, ring substituents, and tertiary carbon atom substituents on the decomposition at 423–473 K of some N-arylcarbamates of tertiary alcohols (p-XC6H4NHCO2C(CH3)2R, where X = CH3, H, Cl, NO2, R=C≡CH, C2H5, CH=CH2) has been investigated. In dodecane, diphenyl ether, acetophenone, nitrobenzene, and decanol, the reactions were first order yielding chiefly carbon dioxide, amine, and olefin. t-Pentyl carbamates yielded the olefins 2-methyl-1-butene and 2-methyl-2-butene in a 3:1 mixture. Solvent effects are reflected in variations in enthalpies and entropies of activation, but effects on the actual values of the specific rate constants are small. Substituent effects are also small, with changes in R from C≡CH to CH=CH2 producing only a tenfold rate increase. Variations in X yield Hammett σρ plots with slopes of about 0.50. These results are consistent with the charge separated cyclic transition state proposed before (1). In ethylene glycol, increased reaction rates and 1:1 yields of the olefins from the t-pentyl carbamates indicate a mechanism with greater carbonium ion character.

Investigation of quantitative structure–reactivity relationships in the aliphatic Claisen rearrangement of bis-vinyl ethers reveals a dipolar, dissociative mechanism

2014 ◽  
Vol 12 (8) ◽  
pp. 1292-1308 ◽  
Author(s):  
Natasha F. O'Rourke ◽  
Jeremy E. Wulff
Keyword(s):  
Vinyl Ether ◽  
Claisen Rearrangement ◽  
Substituent Effects ◽  
Quantitative Structure ◽  
Vinyl Ethers ◽  
Dissociative Mechanism ◽  
Mechanism Of Reaction ◽  
Kinetic Investigations

Kinetic investigations of substituent effects in the Claisen rearrangement of bis-vinyl ether substrates suggest a dissociative mechanism of reaction.

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