Formation of a conjugated oxametallacyclohexadiene by dyotropic rearrangement of bis(2-furyl)zirconocene
作者:Gerhard Erker、Ralph Petrenz
DOI:10.1039/c39890000345
日期:——
Bis(2-furyl)zirconocene (1), obtained from Cp2ZrCl2(Cp =η-cyclopentadienyl) and 2-furyl-lithium, cleanly undergoes dyotropicrearrangement at 185°C to yield the metallacyclic oxazirconacyclohexadiene derivative (2); complex (2) reacts with dimethyl acetylenedicarboxylate at 105°C in a Diels–Alder/retro-Diels–Alder reaction sequence to produce (Cp2ZrO)3 and dimethyl 3-(2-furyl)phthalate (4).
Transition metal-catalyzed dehydrogenation is a clean oxidation method requiring no additional oxidants. We have accomplished a heterogeneous Pd/C-catalyzed aqueous dehydrogenation of 1,4-cyclohexadienes and cyclohexenes to give the corresponding highly-functionalized arenes. Furthermore, various arenes could be efficiently constructed in a one-pot manner via a Diels–Alder reaction and the following