合成路线1

In an alternative route to intermediate (III), ortho-metalation of 1,2-difluorobenzene (XXIV) with n-hexyllithium in THF followed by sequential addition of ZnCl2, CuCl and then chloroacetyl chloride (XXV) gives 2-chloro-2’,3’-difluoroacetophenone (XXVI). Subsequent condensation of chloroketone (XXVI) with vinylmagnesium bromide followed by cyclization of the resulting chlorohydrin (XXVII) under alkaline conditions yields epoxide (XXVIII). This is then coupled with diethyl acetamidomalonate (XXIX) in the presence of Pd(OAc)2 and 1,2-bis(diphenylphosphino)ethane (dppe) to generate the allyl alcohol adduct (XXX), which after conversion to the corresponding mesylate (XXXI) is reacted with 2,2,2-trifluoroethylamine (XXXII) in dimethylacetamide to furnish the allylic amine (XXXIII). Decarbethoxylation of malonate (XXXIII) by heating with LiCl in moist dimethylacetamide provides the N-acetyl aminoester (XXXIV). Then, cyclization of (XXXIV) by means of trifluoroacetic acid in hot toluene gives the azepinone derivative (XXXV). After acidic hydrolysis of acetamide (XXXV), the resulting racemic amine is resolved utilizing (-)-O,O’-di-p-toluoyl-L-tartaric acid (DTTA) in the presence of a trace amount of 5-nitrosalicylaldehyde to provide the (S)-amine ditoluoyltartrate salt (XXXVI). Finally, liberation of the tartrate salt (XXXVI) with HCl in isopropanol and simultaneous hydrogenation of the azepine double bond in the presence of Pd/BaSO4 provides the trans-perhydroazepinone (III) (2-5). Scheme 3.