| Autor: |
Wang D; Process Research and Development Department, Bristol-Myers Squibb Pharmaceutical Research Institute, Princeton, New Jersey 08543, USA., Schwinden MD, Radesca L, Patel B, Kronenthal D, Huang MH, Nugent WA |
| Jazyk: |
angličtina |
| Zdroj: |
The Journal of organic chemistry [J Org Chem] 2004 Mar 05; Vol. 69 (5), pp. 1629-33. |
| DOI: |
10.1021/jo035733r |
| Abstrakt: |
The reaction of a variety of methyl esters with dimethylsulfoxonium methylide at 0-25 degrees C affords the chain-extended beta-keto dimethylsulfoxonium ylides. Subsequent treatment with hydrogen chloride in THF proceeds with loss of DMSO to afford the corresponding alpha-chloroketones. This sequence has been utilized to convert the methyl esters of CBZ-protected alanine and valine to the anti N-protected alpha-amino epoxides, which are important pharmaceutical intermediates. When the same protocol is applied to BOC-protected phenylalanine methyl ester, epimerization occurs so that the use of a more reactive aryl ester is required. This chemistry provides a practical route to alpha-chloroketones that avoids the use of toxic and explosive diazomethane. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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