Ethylene glycol triple bond

Catenane 177, devoid of triple bonds, has been prepared by macrocyclization of a 1,4,5,8-naphthalenetetracar-boxylate diimide precursor bearing ethylene glycol chains and pyromellitic diimide, under standard Mitsunobu alkylation conditions, in the presence of crown ether 170 <20000L449>. 

Rearrangement products at m/z 82 and 96 are dominant in nonbranched alkynes with Cn>g. Consecutive loss of methyl radical occurs. In general, no reliable localization of the triple bond is possible except in derivatives (as in ethylene glycol adducts [1], see scheme). 

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