合成路线1

Ring opening of cyclohexene oxide (I) with phenylmagnesium bromide in the presence of CuI, followed by acetylation of the resulting alcohol (II) gave the racemic trans-2-phenylcyclohexyl acetate (III). Enzymatic resolution of (III) using porcine liver acetone powder yielded the desired (-)-alcohol (II) along with unreacted (+)-acetate (III). Condensation of the sodium alkoxide of benzyl alcohol with bromoacetic acid (IV) afforded benzyloxyacetic acid (V), which was then coupled with the chiral alcohol (-)-(II) to give ester (VI). Hydrogenolysis of the O-benzyl group of (VI), followed by silylation of the resulting hydroxyacetate ester (VII) with triisopropylsilyl chloride, furnished (VIII). Imine (XI) was prepared by condensation of 3-methyl-2-butenal (IX) with p-anisidine (X). The asymmetric cyclocondensation reaction of the lithium enolate derived from ester (VIII) with imine (XI) yielded the chiral beta-lactam (XII). Oxidative removal of the p-methoxyphenyl protecting group of (XII) and then reprotection of the lactam N atom with Boc2O furnished the intermediate N-Boc lactam (XIII).