作者:Karl F. S. Alnes、Leiv K. Sydnes
DOI:10.1007/s00706-006-0441-0
日期:2006.4
Treatment of a number of 2-substituted 1,1,2-tribromocyclopropanes with MeLi at -78 degrees C gave the corresponding 1-bromocyclopropenes, which were reacted with three cyclic dienes to yield the [4 + 2]-cycloadducts. Cycloaddition with 1,3-diphenylisobenzofuran (DPIBF) gave the exo adducts, in most cases in excellent yield, whereas cyclopentadiene afforded endo adducts only, but in moderate yield. In most reactions with furan no adduct was formed, but two 1-bromocyclopropenes derivatives with an aromatic side chain were exceptions and furnished mixtures of exo and endo adducts in moderate yields.