Studies in the Cycloproparene Series: Competitive Pathways in the Dehydrohalogenation Route to 2-Halobicyclo[4.1.0]Hepta-1,3,5-Trienes

Abstract

The (1α,2β,3α,6α)-2,3,7,7-tetrahalobicyclo[4.1.0]heptanes (8a-c), whose structures have been determined by X-ray methods, give 2-halobicyclo[4.1.0]hepta-1,3,5-trienes (5) upon dehydrohalogenation. The 'mixed' halide (8c) and partly labelled [7-¹³c]-(8b,c) have revealed the presence of competing pathways in these conversions. By comparison, dehydrohalogenations of the (1α,3α,4β,6α)-3,4,7,7-tetrahalobicyclo[4.1.0]heptanes (3) give unrearranged 3-halobicyclo[4.1.0]-hepta-1,3,5-trienes (4).