A　series　of　-lactams　containing　the　ferrocene　moiety　were　synthesized　through　the　Staudinger　reaction　between　ferrocenylketene　generated　by　the　thermal　Wolff　rearrangement　of　the　corresponding　diazo　ketone　and　various　imines.　The　stereochemical　outcome　has　been　investigated　and　the　trans-products　were　isolated　as　the　main　products,　opposite　to　the　reported　results　by　Bonini　and　coworkers.　The　absolute　configuration　of　(+/-)-trans-1,4-diphenyl-3-ferrocenylazetidin-2-one　(3c)　was　determined　by　X-ray　analysis.　The　stereoselectivity　is　discussed　from　the　viewpoint　of　the　reaction　mechanism.　[GRAPHICS]　.