Thermal cyclodehydrogenations to form 6-membered rings: cyclizations of [5]helicenes.
Flash vacuum pyrolysis (FVP) of [5]helicene induces a thermal cyclodehydrogenation to form benzo[ghi]perylene. Evidence is presented that supports an electrocyclization-rearomatization mechanism and is inconsistent with mechanistic alternatives involving the intermediacy of aryl radicals or carbenes in the helicene fjord region.
Xue
Xiang
X
Merkert Chemistry Center, Department of Chemistry, Boston College, Chestnut Hill, Massachusetts 02467-3860, USA.
Scott
Lawrence T
LT