Functionalized alkylidenecyclopentenes by acid-catalyzed electrocyclic ring closure of (2Z)-(di)vinylallene acetals

Article abstract of DOI:10.1016/S0040-4039(97)01747-4

Acid-induced electrocyclic ring-closure of (2Z)-4-tert-butyl-3-methyl-2,4,5,7-tetraene acetals 3 afforded a mixture of alkylidenecyclopentene dioxanes Z-4 and E-4. The lack of torquoselective effects on the electrocyclization suggested the transition stat