A new seven-membered annulation method that employs (Z [hair space])-5-iodo-1- tributylstannylpent-1-ene (1) as a key reagent and that is exemplified by the conversion of compounds 6, 12, 13, 20, 25, and 26 into the annulation products 11, 18, 19, 24, 33, and 34, respectively, is reported.
