Syntesestudier av barkbilleferomonet ipsdienol

Abstract

I denne oppgaven ble det forsøkt å utføre to ulike syntesestrategier for ipsdienol praktisk. Begge disse gir racemisk ipsdienol. Den første strategien ble utført flere ganger, der 2-metylbut-3-yn-2-ol ble dehydrert til 2-metylbut-1-en-3-yn. Dette trinnet var vellykket og ga utbytte på 46 %, men videre omdannelse til dilitiert 2-metylbut-1-en-3-yn og deretter 2-metyl6-metylenokta-2-en-7-yn-4-ol var utfordrende. Flere parametere som temperatur og fukteksponering ser ut til å tåle lite endring, og det er dermed konkludert med at strategien er sensitiv. Produktet 2-metyl-6-metylenokta-2-en-7-yn-4-ol ble kun isolert én gang, men i lavere utbytte og renhet enn i litteraturen. Den ble deretter redusert til målmolekylet ipsdienol. Den andre syntesestrategien ble påbegynt og resultatene indikerer at den kan være vellykket så langt. Først ble 7-metyl-3-metylenokta-1,6-dien epoksidert til 2,2-dimetyl-3-(3-metylenpent-4-enyl)oksiran, der utbyttet ble estimert til 61 %. Videre ble denne forsøkt omdannet til 2-metyl-6-metylenokta-3,7-dien-2-ol og 1 H NMR-spekteret indikerer at denne er dannet. Opprensning av råoljen ville vært nødvendig for å fastslå dette.

In this thesis, two different synthesis strategies of ipsdienol were attempted. Both of these gave racemic ipsdienol. The first strategy was performed several times, where 2-methylbut-3-yn-2-ol was dehydrated to 2-methylbut-1-en-3-yn. This step was successful and yielded 46 %, but further conversion to dilithiated 2-methylbut-1-en-3-yn and then 2-methyl-6-methyleneocta-2-en-7-yn-4-ol was challenging. Several parameters like temperature and exposure to moisture may seem to withstand little change, and therefore it is concluded that the strategy is sensitive. The product 2-methyl-6-methyleneocta-2-en-7-yn-4-ol was isolated once, but in lower yields and purity than stated in the literature. It was subsequently reduced to the target molecule, ipsdienol. The second synthesis strategy was started and the results seem to be successful so far. First, 7-methyl-3-methyleneocta-1,6,-dien was epoxidated to 2,2-methyl-3-(3-methylpent-4-enyl)oxirane, where the yield was estimated to 61 %. Further, it was attempted to convert this to 2-methyl-6-methyleneocta-3,7-dien-2-ol and the 1 H NMR-spectrum indicates that the compound is formed. Purification steps would be necessary to determine this.