Author:
Ferber PH,Gream GE,Kirkbride PK,Tiekink ERT
Abstract
A number of 7-alkylidenecycloocta-1,3,5-trienes, all unstable, yield novel π8+π2 cycloadducts with a range of π2-addends. The reactions of 7-methylenecycloocta-1,3,5-triene with ethene-tetracarbonitrile, 4- phenyl-1,2,4-triazoline-3,5-dione, diethyl azodicarboxylate and chlorosulfonyl isocyanate are described. The tetraene did not react with maleic anhydride or dimethyl acetylenedicarboxylate. As well, the reactions of 1,3,5-trimethyl-7-methylenecycloocta-1,3,5-triene, 2,9a- dihydro-1H-cyclopentacyclooctene and 1,2,3,10a- tetrahydrobenzocyclooctene with ethenetetracarbonitrile and of 7- isopropylidenecycloocta-1,3,5-triene with 4-phenyl-1,2,4-triazoline- 3,5-dione are discussed. The intermediacy of homotropylium zwitterions in the reactions is postulated.