(5S,9S)-8-(Z)-benzylidene-2-((2S,3R)-(Z)-3-but-1-enyloxiranyl)-3-methyl-9-triethylsiloxy-1-oxa-7-azaspiro[4.4]non-2-ene-4,6=-dione

(5S,8S,9R)-8-benzoyl-2-((1S,2R)-(Z)-1,2-epoxyhex-3-enyl)-8-hydroxy-3-methyl-6,9-bis-triisopropylsiloxy-1-oxa-7-azaspiro[4.4]nona-2,6-dien-4-one

(5S,8S,9R)-8-benzoyl-2-((1S,2R)-(Z)-1,2-epoxyhex-3-enyl)-8-methoxy-3-methyl-9-triisopropylsiloxy-1-oxa-7-azaspiro[4.4]non-2-ene-4,6-dione

(3S,4S)-5-(Z)-benzylidene-3-((4R,5R)-(Z)-4,5-epoxy-3-hydroxy-2-methylnon-6-enoyl)-3-hydroxy-4-triisopropylsiloxypyrrolidin-2-one

(3S,4S)-3-{3-[(2R,3R)-((Z)-3-But-1-enyl)-oxiranyl]-3-hydroxy-2-methyl-propionyl}-3-hydroxy-5-[1-phenyl-meth-(Z)-ylidene]-4-triethylsilanyloxy-pyrrolidin-2-one