Abstract Geminal dibromocyclopropanes annelated to six-, seven-or eight-membered rings can be converted easily to their geminal endo-lithio-exo-bromo derivatives when treated with butyllithium at− 95. Upon reaction of these derivatives with iodine at− 95 the corresponding geminal endo-iodo-exo-bromocyclopropanes are obtained in good yields. The structure assignments are made by means of some silver ion-assisted ring ...
