Treatment of 2,2-dimethyl-6-nonene-4,8-diynal (2) with CeCl3/LiN(TMS)(
2) at -5 similar to 25 degrees C gave 2,2-dimethyl-1-indanol (3) in a
moderate yield. In the present study, acyclic (Z)-enediyne aldehyde (2
) was cyclized to afford a nine-membered monocyclic enediyne (7), whic
h cycloaromatized spontaneously at room temperature.