Ether, 2-octenyl vinyl

The 3,3 sigmatropic leairangement of 2-octenyl vinyl ether (39) afforded 3-pentyl-4-pentenal (40) in 79% yield. The terminal double bond was converted to the methyl ketone (41) in 90% yield. The keto aldehyde (41) was converted to S-pentyl-2-cyclopentenone (42). The double bond migration gave 2-pen-tyl-2-cyclopentenone (dihydronotjasmone), which was converted to methyl dihydiojasmonate (43 Scheme 1 l).t08409 similarly, dihyctojasmone was synthesized from 2-octenyl allyl ether. 

Conjugate addition of vinyllithium or a vinyl Grignard reagent to enones and subsequent oxidation afford the 1.4-diketone 16[25]. 4-Oxopentanals are synthesized from allylic alcohols by [3,3]sigmatropic rearrangement of their vinyl ethers and subsequent oxidation of the terminal double bond. Dihydrojasmone (18) was synthesized from allyl 2-octenyl ether (17) based on Claisen rearrangement and oxidation[25] (page 26). 

Vinyl 2-octenyl ether 106, obtained from 2,7-octadienyl acetate (56) is converted to the aldehyde 107 in 79% yield by [3,3] sigmatropic rearrangement at 183-190 C.Then PdCl2-catalyzed oxidation of the double bond to the ketone 108 followed by intramolecular aldol condensation gives the 2-cyclopentenone 109 in 68% yield, which is converted to methyl dihydrojasmonate (ii0)40. Treatment of allyl 2-octenyl... 

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