REGIOSELECTIVE REACTIONS OF 2,3-ENDO-EPOXYBICYCLO[3.2.0]HEPTANONE ETHYLENE ACETAL INVOLVING ORGANOMETALLIC REAGENTS

The preparation of (1′α,2′α,4′α, 6′α)-spiro{[1,3]dioxolan-2,7′-[3′]oxatricyclo[4.2.0. 02′,4′]octane} (3) and its reaction with various organometallic reagents is described. Attack occurred at C-2 preferentially (selectivity 67-83%) due to the influence of the neighbouring cyclobutane ring on the relative energies of the transition states leading to epoxy-ring opening. The conformation of the bicyclo[3.2.0] heptane system in the products is discussed.