Use of epoxidation and epoxide opening reactions for the synthesis of highly functionalized 1-oxaspiro[4.5]decan-2-ones and related compounds

Abstract Epoxidation of ethyl 3-(6-hydroxycyclohex-1-en-1-yl)propanoate ( 11 ) provided the syn epoxide 12 . By invoking chelation controlled epoxide opening the triol derivatives 13 and 14 or the spiro lactone 25 could be obtained. Elimination of HBr from the bromides 26 and 27 produced the spiro cyclohexenones 28 and 29 . Epoxidation of the double bond occurred in a diastereoselective manner to give epoxides 30 and 31 , respectively. Treatment of the epoxide 31 with LiBr/AcOH gave the bromo hydrin 38 . In a ‘merry go round’ fashion 38 was further functionalized on the cyclohexane ring by elimination, epoxidation, and epoxide opening resulting in the bromo hydrin 43 . Other cyclohexane derivatives that were produced during these studies include the cyclohexenone 19 and the cyclohexanediol 23 . In addition, enolate azidation of the spiro lactone 29 proceeded in a diastereoselective manner providing the α-azido lactone 32 .