- STEREOCHEMICAL STUDIES - LVII. SYNTHESIS OF OPTICALLY ACTIVE COMPOUNDS BY THE NOVEL USE OF MESO-COMPOUNDS -1. EFFICIENT SYNTHESIS OF TWO STRUCTURAL TYPES OF OPTICALLY PURE PROSTAGLANDIN INTERMEDIATES.
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With an aim to overcome several inefficient aspects of ordinary methods of preparing optically active compounds, we have developed a new method which recommends utilization of symmetrically functionalized meso-compounds in place of racemic compounds.As shown in Scheme 1, when the meso-compound (I) is monofunctionalized by an optically active functional group (A) and each of the formed diastereomers (II and III) is subjected to further chemical elaborations including protective group transposition, it is theoretically possible to convert the total amount of the starting material (I) into the requisite optically pure product (VI or VII) by selecting synthetic schemes.By employing this novel concept, two structural types of the prostaglandin intermediates ((-)- and (+)-2a,b) have been prepared from the meso-diols (1a,b) by way of the two diastereomeric monoesters (13a,b and 14a,b) which are produced by the reactions 1a,b with N-mesyl- and N-phthaloyl-(S)-phenylalanyl chloride (3a,b).
- Nara, M,Terashima, S.,Yamada, S.
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p. 3161 - 3170
(2007/10/02)
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- Novel monoesters of cis-cyclopentenediol, process for preparation thereof, and process for preparation of lactones from the monoesters
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A novel monoester of cis-cyclopentenediol of the following formula STR1 wherein STR2 is an optically active acyl moiety. The monoester can be prepared by reacting cis-2-cyclopentene-1,4-diol with an optically active carboxylic acid of the following formula STR3 wherein STR4 is the same as defined above, or its reactive derivative, and separating the resulting reaction product into the two individual diastereomers. Lactones can be prepared from the monoesters selectively and with commercial advantage.
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