induction in the iodocarbocyclizationreaction of 4-pentenylmalonate derivatives having a stereogenic center at an allylic or a homoallylic position has been investigated. The iodocarbocyclizationreactions of 3-oxy-4-pentenylmalonate derivatives proceeded with high cis-selectivity through stereoelectronic control of the oxygenated substituent at an allylic position. In the reaction of (S)-2-siloxy-4-pentenylmalonate