| Popis: |
Treatment of 6,6-dichloro-3-oxabicyclo[3.1.0]-hexane (7) with potassiumt-butoxide generates the ring-strained cyclopropene8 as a reactive intermediate. With 1,3-diphenylisobenzofuran compound8 is trapped as a ∼5∶1 mixture of theexo- andendo-adducts11a and11b, respectively. With furan only the ring expanded vinylcarbene12 is intercepted and spirocycle13a is formed. Carbene12 is also captured by cyclohexene, 2,3-dihydrofuran, 2,5-dihydrofuran, and diphenylethyne to give22–25 respectively. A likely side product in these reactions is the pyran14. |
Plný text