SYNTHESIS OF SUBSTITUTED BICYCLO[2.2.2]OCTATRIENES

An efficient route to bicyclo[2.2.2]octatriene, barrelene, and substit uted versions of this molecule has been developed starting from the be nzene equivalent cis-3,5-cyclohexadiene-1,2-diol. Following the Diels- Alder reaction of this molecule with an activated acetylene, conversio n of the diol to the final olefin was accomplished through formation o f a thiocarbonate intermediate and subsequent reaction with 1,3-dimeth yl-2-phenyl-1,3,2-diazaphospholidine (DPD). The synthesis developed al lows a variety of barrelenes to be prepared in as few as three steps f rom commercially available starting materials.