(1S,5S,6S)-6-(3-hydroxypropyl)-5-methylethenylbicyclo<3.2.1>octan-2-one ethylene acetal

(1S,5S,6S)-5-acetyl-6-(3-hydroxypropyl)bicyclo<3.2.1>octan-2-one 2,2-ethylene acetal

(1S,5S,6S)-5-methylethenyl-2-spiro(2,5-dioxolane)bicyclo<3.2.1>octane-6-propanal

(8S,9S,12S)-4,5-didehydro-17,18,19-trisnoraphidicolin-3,16-dione 16,16-ethylene acetal

(5S,8S,9S,12S)-3,4-didehydro-3-trimethylsiloxy-17,18-dinoraphidicolin-16-one ethylene acetal