TY - JOUR
T1 - Electron transfer induced deprotonation of α-and β-pinene
T2 - Evidence for ring-closed vinylcyclobutane radical cations
AU - Zhou, Dahui
AU - Sheik, Mohsin
AU - Roth, Heinz D.
N1 - Funding Information:
Hydrogen migrations have been demonstrated for several radical cations, based on EPR or CIDNP spectra, 10a-e isotopic labeling studies, 10f or theoretical calculations. 11 The conversion of cyclohexane-1,4-diyl to cyclohexene 10a,b or cyclopentane-l,3-diyl to cyclopentene 10c radical cations rests on EPR evidence; the conversion of benzonorcaradiene to 1-and 2-methylnaphthalene, 10d and of tricyclo\[4.1.0.02,7\]heptane to bicyclo\[4.1.0\]hex-2-en1e0 e is based on CIDNP data; the hydrogen migration in sabinene radical cation rests on the chirality of the product, 13-phellandrene;l°fand the conversion of cyclopropane to propene radical cation has been investigated by ab-initio calculations. 11 The minor pathway tentatively proposed for the conversion of 1 to 10 would be a 1,3-hydrogen shift; this interesting reacdon type is under active investigation. Acknowledgement Financial support of this work by the National Science Foundation by grant NSF CHE-9414271 and an equipment grant NSF USE-9250530 (supporting the work of MS) is gratefully acknowledged.
PY - 1996/4/1
Y1 - 1996/4/1
N2 - Electron transfer from α-(1) or β-pinene (2), to 2,3,5,6-tetrachlorobenzoquinone generates radical cations, which are rapidly deprotonated by the semiquinone radical anion. (1S,5S)-2 is converted to (1S,5S)-1 and (1R,5R)-1 yields a dehydrogenation product, verbenene, (1R,5R)-9 with essentially quantitative retention of optical activity. The results support chiral, "ring-closed" radical cation structures in which the allylic-quaternary cyclobutane C-C bond retains a significant degree of bonding.
AB - Electron transfer from α-(1) or β-pinene (2), to 2,3,5,6-tetrachlorobenzoquinone generates radical cations, which are rapidly deprotonated by the semiquinone radical anion. (1S,5S)-2 is converted to (1S,5S)-1 and (1R,5R)-1 yields a dehydrogenation product, verbenene, (1R,5R)-9 with essentially quantitative retention of optical activity. The results support chiral, "ring-closed" radical cation structures in which the allylic-quaternary cyclobutane C-C bond retains a significant degree of bonding.
UR - http://www.scopus.com/inward/record.url?scp=0029878332&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0029878332&partnerID=8YFLogxK
U2 - 10.1016/0040-4039(96)00332-2
DO - 10.1016/0040-4039(96)00332-2
M3 - Article
AN - SCOPUS:0029878332
SN - 0040-4039
VL - 37
SP - 2385
EP - 2388
JO - Tetrahedron Letters
JF - Tetrahedron Letters
IS - 14
ER -