Aluminum carbenoids in the cyclopropanation of fulvenes

Аннотация

Aluminum carbenoid Et₂AlCH₂I reacts with 6-substituted fulvenes to give tricyclopropanes in high yields. Calculations at the B3LYP/6-31G(d) level of theory show that coplanar arrangement of the double bonds facilitates cyclopropanation due to conjugation in the transition state. Aluminum carbenoid Et₂AlCH₂I was generated by either the reaction of equimolar amounts of Et₃Al and CH₂I₂ in hexane or treatment of Et₂AlI with CH₂N₂ in dichloromethane.