合成路线1

The enantiocontrolled addition of phthalimide (I) to 1,3-butadiene monoepoxide (II) with a chiral palladium catalyst and Na2CO3 in dichloromethane gives N-(2-hydroxy-1(S)-vinylethyl)phthalimide (III), which is treated with triflic anhydride and TEA in dichloromethane to yield the triflate (IV). The condensation of (IV) with dimethyl malonate (V) by means of NaH in THF affords the alkylated malonate (VI), which is finally decarboxylated and deprotected by a treatment with aqueous refluxing HCl. Note that the synthesis of the biologically active (S)-enantiomer simply requires a change in the chirality of the Pd catalyst used in the first step of the synthesis.