| 摘要 |
PCT No. PCT/IB95/00505 Sec. 371 Date Feb. 7, 1996 Sec. 102(e) Date Feb. 7, 1996 PCT Filed Jun. 21, 1995 PCT Pub. No. WO96/00206 PCT Pub. Date Jan. 4, 1996A method for preparing 3-oxo-2-pentyl-1-cyclopentaneacetic acid or methyl 3-oxo-2-pentyl-1-cyclopentaneacetate, essentially in the form of the (+)-(1R)-cis isomer thereof. The method includes the steps of (a) catalytically hydrogenating a compound of the formula (I), <IMAGE> (I) wherein M is a hydrogen atom, an alkali metal or alkaline earth metal atom, or a group NR4, where R is a hydrogen or a lower alkyl radical, in a suitable solvent and in the presence of a catalyst consisting of an Ru(II) complex comprising chiral ligands that contain a 2,2'-bis(diphenylphosphino)-1,1'-dinaphthyl (BINAP) radical or a 1,2-bis(2,5-dialkylphospholano)benzyl (DuPHOS) radical, wherein the alkyl is a C2 or C3 radical, to give a compound of formula (II), <IMAGE> (II) wherein M has the meaning given above, essentially in the form of the (+)-(1R)-cis isomer thereof; (b) if required, acidifying, in a per se known manner, the compound of formula (II), wherein M is an alkali metal or alkaline earth metal atom, or a group N4, where R is hydrogen or a lower alkyl radical, to give (+)-(1R)-cis-3-oxo-2-pentyl-1-cyclopentaneacetic acid; and (c) if required, esterifying the resulting (+)-(1R)-cis-3-oxo-2-pentyl-1-cyclopentaneacetic acid under suitable conditions to form methyl (+)-(1R)-cis-3-oxo-2-pentyl-1-cyclopentaneacetate. |
