Anions of allylmeldrum's acids reacted with phenyl(propynyl)iodonium salt to produce bicyclo[3.1.0]hex-1-enes as the reactive intermediates through cyclopropanation reaction to yield various dimerization products. Depending on the substitution pastern on the intermediates. various dimeric products were obtained. (C) 2001 Elsevier Science Ltd. All rights reserved.