Intramolecular
2-Propynyldiarylacetylenes undergo thermal intramolecular [4 + 2] cycloaddition to give benzo[b]fluorene derivatives in good yields. The hybridization of the tether connecting the reacting alkynes has a pronounced effect on the course of the reaction. Theoretical calculations and isotopic labeling studies support a mechanism which involves the generation of a cyclic allene intermediate that evolves to the final benzo[b]fluorene.
Rodriguez
D
Departamento de Quimica Organica y Unidad Asociada al CSIC, Facultad de Quimica, Universidad de Santiago de Compostela. 15706 Santiago de Compostela, Spain.
Navarro
A
Castedo
L
Dominguez
D
Saa
C