
TY  - JOUR
A1  - Beckwith, ALJ 
A1  - Glover, SA 
T1  - Determination of the Rates of Ring-Closure of Oxygen-Containing Analogs of Hex-5-Enyl Radical by Kinetic Electron Spin Resonance Spectroscopy
JF  - Australian Journal of Chemistry
JO  - Aust. J. Chem.
Y1  - 987
VL  - 40
IS  - 1
SP  - 157
EP  - 173
KW  - 
UR  - https://doi.org/10.1071/CH9870157 
N2  - The hex-5-enyl (1), 3-oxahex-5-enyl (6), 2-oxahex-5-enyl (9) and 2,2-dimethylbut-3- enoyloxymethyl (13) radicals have been generated by interaction of the corresponding bromides with trialkyltin or trialkylgermanium radicals, and their rate constants and activation parameters for cyclization have been determined by kinetic e.s.r . spectroscopy. The 3-oxa species (6) undergo 1,5-ring closure more rapidly than does hex-5-enyl radical (1) because of favourable  stereoelectronic factors. Spectral evidence has been obtained for restricted rotation about the O-CH2* bond in the 2-oxa radical (9) as a consequence of which its ring closure is relatively slow. Similarly, 1,5-ring closure of the ester derived radical (13) is slow because of unfavourable conformational effects arising from restricted rotation about the CO-O bond. The radical (22) formed from allyl bromoacetate does not undergo ring closure. Spectral data have been obtained for various radicals (16), (19), (23), (24) formed by intermolecular addition. 
ER  -

