(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

(2S,3R)-(Z)-2,3-epoxy-hept-4-enal

(5S,9S)-8-(Z)-benzylidene-2-((1S,2R)-(Z)-1,2-epoxy-hex-3-enyl)-3-methyl-9-trimethylsilyloxy-1-oxa-7-azaspirop[4.4]non-2-ene-4,6-dione