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Rearrangements of free radicals, XI. Sigmatropic and electrocyclic reactions of bicyclo[3.2.0]heptadienyl radicals, 3‐Quadricyclanyl radicals, and 7‐norbornadienyl radical
Author(s) -
Sustmann Reiner,
Brandes Dieter,
Lange Fritz,
Nüchter Ursula
Publication year - 1985
Publication title -
chemische berichte
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 0009-2940
DOI - 10.1002/cber.19851180907
Subject(s) - chemistry , radical , bicyclic molecule , free radical reaction , medicinal chemistry , organic chemistry
The rearrangement of matrix‐isolated organic radicals with bicyclo[3.2.0]heptadienyl structure ( 2, 5, 11a,b ), 3‐quadricyclanyl structure ( 16, 26, 27 ), and of 7‐norbornadienyl radical 15 is studied. Final rearrangement products are radicals with tropylium structure. 16, 26 , and 27 isomerize to radicals with bicyclo[3.2.0]heptadienyl skeleton before electrocyclic ring opening to tropylium radicals takes place. 7‐Norbornadienyl radical 15 is the least stable radical on the C 7 ‐hypersurface. Sigmatropic 1,2‐vinyl shifts in bicyclo[3.2.0]heptadienyl radicals could not be observed. Substituents do not influence the rearrangement behaviour.