合成路线1

An enantioselective total synthesis of chloride (MOM-Cl) and NaH in THF gives the methoxymethyl ether (II), which is methylated with n-BuLi and methyl iodide in THF yielding the 6-methyl derivative (III). The condensation of (III) with 3-methyl-2-butenyl bromide (IV) by means of s-BuLi in THF affords compound (V), which is deprotected with LiBF4 and TMSCl in acetonitrile to give the phenol (VI). Methylation of (VI) with dimethyl sulfate and K2CO3 in refluxing acetone provides the ether (VII), which is hydroxylated at the terminal methyl group with SeO2 and tert-butyl hydroperoxide (TBHP) in dichloromethane giving alcohol (VIII). The reaction of (VIII) with methanesulfonyl chloride and then with LiBr affords the corresponding alkenyl bromide (IX), which is condensed with methyl acetoacetate (X) by means of NaH and n-BuLi in THF providing the ketoester (XI).