Ein effizienter Zugang zu 1,5-Dihydropentalen und 2-Methyl-1,5-dihydropentalen aus Acrolein und Methacrolein

Article abstract of DOI:10.1055/s-1990-26815

Acrolein and methacrolein can be converted into 1,5-dihydropentalene and its 2-methyl derivative, respectively, by a simple, three-step process. <4+2> Cycloaddition of the aldehydes with cyclopentadiene affords 5-formyl-2-norbornenes which readily undergo condensation with cyclopentadiene to give 5-(cyclopentadienylidenemethyl)-2-norbornenes.These protected 6-vinylpentafulvenes undergo retro-cleave to cyclopentadiene and the 1,5-dihydropentalenes on vacuum flash thermolysis.