The β-(Phosphatoxy)alkyl Radical Rearrangement. Rate Constants, Arrhenius Parameters, and Structure Activity Relationships

1996 ◽  
Vol 118 (28) ◽  
pp. 6666-6670 ◽  
Author(s):  
David Crich ◽  
Xian-Yun Jiao
Keyword(s):  
Rate Constants ◽  
Alkyl Radical ◽  
Arrhenius Parameters ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Radical Rearrangement

Rate constants and Arrhenius parameters for the reaction of a primary alkyl radical with tributylgermanium hydride

1983 ◽  
Vol 105 (11) ◽  
pp. 3578-3580 ◽  
Author(s):  
J. Lusztyk ◽  
B. Maillard ◽  
D. A. Lindsay ◽  
K. U. Ingold
Keyword(s):  
Rate Constants ◽  
Alkyl Radical ◽  
Arrhenius Parameters

A homoallyl radical rearrangement. Kinetics of the isomerization of the 2,2-dimethyl-3-buten-1-yl radical to the 1,1-dimethyl-3-buten-1-yl radical

1983 ◽  
Vol 61 (6) ◽  
pp. 1077-1081 ◽  
Author(s):  
Chryssostomos Chatgilialoglu ◽  
Keith U. Ingold ◽  
Irene Tse-Sheepy ◽  
John Warkentin
Keyword(s):  
Temperature Dependence ◽  
Epr Spectroscopy ◽  
Rate Constants ◽  
Alkyl Radical ◽  
Spin Trapping ◽  
Ring Closure ◽  
Rate Enhancement ◽  
Radical Rearrangement ◽  
Kinetics Of

Rate constants for the overall rearrangement of the 2,2-dimethyl-3-buten-1-yl radical to the 1,1 -dimethyl-3-buten-1-yl radical, kC=C, have been measured from −145 °C to −101 °C by kinetic epr spectroscopy and at 40 °C by spin trapping with 1-methyl-4-nitroso-3,5-diphenylpyrazole. The temperature dependence can be represented by[Formula: see text]where θ = 2.3RT kcal mol−1. This rearrangement, which must proceed via a 2,2-dimethylcyclopropylcarbinyl radical as an intermediate, is one of the fastest rearrangements involving a primary alkyl radical. At 25 °C, kC=C = 4.3 × 107 s−1, which makes this rearrangement about 10 000 times faster than the rearrangement of the simplest homoallyl radical, 3-buten-1-yl. This rate enhancement is attributed to steric acceleration of ring closure by the gem dimethyl groups (Thorpe–Ingold effect).

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