SYNTHESIS OF PHOTORESPONSIVE POLYETHERS

A Diels-Alder, retro Diels-Alder sequence provides access to 2,3,5-tri - and 2,3,5,6-tetraester-substituted norbornadienes. Attempts to reduc e the norbornadiene esters with LiAlH4 failed. The corresponding quadr icyclanes, which are available by photoisomerization of the norbornadi enes give the alcohols in 32 and 74% yield. The quadricyclane alcohols 2a-c are converted with methyl iodide to compounds 3a-c or with 2-met hoxyethyl 4-toluenesulfonate to the ''tentacle molecules'' 4a-c. A num ber of catalysts were tested to reisomerize the ''tentacle'' quadricyc lanes to the nor bornadienes, Neutral aluminum oxide proved to be most effective. In preliminary studies the tentacle quadricyclanes exhibit excellent complexing properties for Na+ and K+ whereas the norbornadi ene isomers are less effective complexing agents.