合成路线1

In an alternative method, (-)-myrtenol (VI) was heated with triethyl orthoacetate to produce an intermediate allyl vinyl ether (VII), which underwent Claisen rearrangement to the unsaturated ester (VIII). Ozonization of the olefin (VIII), followed by reductive treatment with trimethyl phosphite, furnished ketone (IX). Conversion of ketone (IX) into the required amine (XI) was effected via previous formation of either the oxime (XII) or the O-methyl oxime (X). Simultaneous reduction of the O-methyl oxime and ester functions of (X) was carried out by using NaBH4 in the presence of AlCl3 or, alternatively, with sodium metal and n-propanol, to produce the desired (2R,3R)-amino alcohol (XI) as the major diastereoisomer. Isolation of (XI) from the reaction mixture was achieved through formation of the corresponding benzoate salt. Amino alcohol (XI) was also obtained by reduction of oxime (XII) with NaBH4 in the presence of either boron trifluoride ethearate or TiCl4. Optionally, (X) was reduced in a two-step process by first conversion to alcohol (XIII) and subsequent reduction of the oxime function. Acid chloride (XIV) was prepared from 5-hydroxybenzothiophene-3-carboxylic acid (I) by sulfonylation of the phenolic hydroxyl with benzenesulfonyl chloride, followed by treatment with SOCl2. Condensation of acid chloride (XIV) with amine (XI) produced the corresponding amide (XV). The alcohol function of (XV) was oxidized to aldehyde (XVI) using NaOCl in the presence of catalytic amounts of TEMPO and KBr. Then Wittig condensation of aldehyde (XVI) with (4-carboxybutyl)triphenylphosphonium bromide (XVII), followed by basic hydrolysis of the phenylsulfonyl protecting group, gave rise to the title compound.