New reactivity of 6,6-bis-donor-substituted pentafulvenes: one-step synthesis of highly substituted [3]cumulene and dihydropentalene

作者：Kerisit Nicolas; Finke Aaron D; Trapp Nils; Leroux Yann R; Guillernin Jean Claude; Trolez Yann; Diederich Francois^*

来源：Tetrahedron, 2015, 71(25): 4393-4399.

DOI：10.1016/j.tet.2015.03.081

• Pentafulvenes
• [2+2] Cycloaddition
• Electrocyclization
• [3]Cumulene
• dihydropentalene

We report the preparation of a 6,6-bis[(4-N,N-dimethylanilino)ethynyl]pentafulvene from a 6,6-dibromopentafulvene and 4-ethynyl-NN-dimethylaniline under Sonogashira cross-coupling conditions. A push pull [3]cumulene was formed unexpectedly during this reaction in moderate yield. The 6,6-bis [(4-N,N-dimethylanilino)ethynyl]pentafulvene was reacted with tetracyanoethylene, and an unprecedented 1,2-dihydropentalene was obtained in high yield as the exclusive product. The structures of the new compounds are supported by X-ray analysis, and a reasonable mechanism for their formation is proposed. We also report their interesting opto-electronic properties, as studied by UV/vis spectroscopy and cyclic voltammetry (CV).

• 出版日期2015-6-24