合成路线1

The condensation of aldehyde (I) with boronate (II) in toluene gives the chiral alcohol (III), which is treated with Tbdms-OTf and TEA to yield the silyl ether (IV). The hydroxylation of the terminal double bond of (IV) by means of 9-BBN in refluxing THF affords the primary alcohol (V), which is oxidized by means of the Swern oxidant to provide the aldehyde (VI). The homologation of (VI) with methyltriphenylphosphonium iodide (VII) and NaHMDS gives the unsaturated compound (VIII), which is deprotected at the ketonide group by means of TFA in dichloromethane to afford the diol (IX). The dehydration of (IX) by means of tosylimidazole (X) and NaH in THF provides the epoxide (XI), which is condensed with the Grignard reagent (XIII) (obtained by reaction of the tributyltin derivative (XII) with MgBr2) to give the secondary alcohol (XIV). The reaction of 2-allyl-6-methoxybenzamide (XV) with I2 in THF/water gives the lactone (XVI), which is treated with Zn and AcOH to yield 2-allyl-6-methoxybenzoic acid (XVII). The esterification of acid (XVII) with alcohol (XIV) by means of DEAD and PPH3 affords the corresponding ester (XVIII), which is submitted to a ring closing metathesis reaction by means of a Ru catalyst to provide the macrolactone (XIX). The cleavage of the Pmb protecting group of (XIX) by means of DDQ gives the primary alcohol (XX), which is oxidized to the aldehyde (XXI) by means of DMP oxidant.