ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Methionine as Precursor for the Enantioselective Synthesis of α-Branched Vinylglycines and of Other Amino AcidsMethionine is converted by previously published methods into the diastereoisomerically pure 3-thiabutyl-substituted oxazolidinone (7) and imidazolidinones 5 and 6. An X-ray crystal structure determination of cis-3-benzoyl-2-(tert-butyl)-4-(3-thiabutyl)oxazolidin-5-one (7) confirms the configurational assignments made by NOE-NMR measurements. Oxidation to sulfoxides and pyrolytic elimination produce vinyl-substituted heterocycles (see 19, 21). Diastereoselective alkylations of the enolate 14 from the imidazolidinone 5 and of the dienolate 23 from the vinyl derivative 19 give geminally alkyl- and/or vinyl-substituted heterocycles. Some of these products were hydrolyzed to free amino acids, such as (R)-2-methyl- (25a) and (R)-2-ethyl-2-vinylglycine (25b) (R)-2-methylhomoserine (27). Raney-Ni desulfurization of 5 and oxidative degradation of 19 lead to enantiomerically pure derivatives of α-aminobutyric acid (see 28) and of glycine (see 31), respectively.
Additional Material:
2 Ill.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19860690611
