THE INVERSE ELECTRON-DEMAND DIELS-ALDER REACTION IN POLYMER SYNTHESIS .1. A CONVENIENT SYNTHETIC ROUTE TO DIETHYNYL AROMATIC-COMPOUNDS

The simple procedure whereby acetophenone derivatives are converted, by reaction with phosphoryl chloride and N,N-dimethylformamide, into beta-chlorocinnamaldehydes. and thence, by base-induced elimination, into ethynylarenes, has been extended to diketones of the type MeCOC(6)H(4)COMe (m- and p-) and (p-MeCOC(6)H(4))(2)X (X = O, S, SO2, CH2, CO, or a single bond): the corresponding diethynyl compounds are obtained by this route in acceptable yield. 1,3,5-Triacetylbenzene is similarly converted into 1,3,5-triethynylbenzene.