The treatment of a series of 1-aryl-2,2-dihalocyclopropanes with t-BuOK at -10 C produces the corresponding 1-aryl-2-halocyclopropenes, which react with cyclopentadiene to produce fairly good yield of [4+2]-cycloaddition products with more than 90% of the endo-isomer. The higher yield obtained from hexane medium then from methanol and ionic liquid demonstrates that the reaction is a nonpolar process.
Relation:
JOURNAL OF THE CHINESE CHEMICAL SOCIETY,61(2),285–289.
