COMPETING 1,N-ELIMINATION REACTIONS OF 1-BROMO-5-BROMOMETHYL-6,6-DICHLOROBICYCLO[3.1.0]HEXANE - A STRAINED 1,3-BRIDGED CYCLOPROPENE AND A VINYLCARBENE AS REACTIVE INTERMEDIATES

摘要

1-Bromo-5-bromomethyl-6,6-dichlorobicyclo[3.1.0]hexane (9) was treated with alkyllithium at different temperatures. After halogen metal exchange in 9, two competing 1,n-elimination reactions take place. A 1,2-elimination of organolithium compound 12 leads to strained 1,3-bridged cyclopropene 10 which undergoes a cyclopropene-vinylcarbene rearrangement to 17. Insertion of 17 into the ether solvent affords isomers Iga and 18b. In contrast, 1,4-eliminations of organolithium compound 13 generate butadienes 14 and 16, respectively. The formation of the products is temperature dependent. Copyright (C) 1996 Elsevier Science Ltd [References: 56]