MARCH 1966 ALKYLIDENECYCLOPROPANES FROM ALLENES 773 furan. The discovery by Simmons and Smiths of the simple general method for the synthesis of cyclopropanes from olefins by reaction with methylene iodide and zinc-copper couple provided another pathway to alkylidenecyclopropanes. This was exploited by U11-man and Fran~ hawe,~ who treated methyl penta-3, 4-dienoate (1) with the Simmons-Smith reagent and obtained ...
