- Towards a greener synthesis of (S)-3-aminobutanoic acid: Process development and environmental assessment
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An improved, greener process for the enantioselective chemoenzymatic synthesis of (S)-3-aminobutanoic acid has been developed. Reaction steps comprise an initial aza-Michael addition starting from cheap prochiral compounds, subsequent enzymatic resolution via aminolysis using commercially available Candida antarctica lipase B in a solvent-free one-pot process, hydrolysis of the resulting ester and removal of the N-benzyl moiety via hydrogenation. After isolation, the desired (S)-3-aminobutanoic acid was obtained in an overall yield of 28% and with an excellent enantiomeric excess of 99% ee. Notably, this reaction sequence does not require column chromatography with organic solvents and only one purification step of an intermediate is needed. The environmental impact of this optimized process has been evaluated and an E-factor of 41 has been calculated for the overall process. A comparative assessment with the previous process was done via mass balancing using the E-factor, the selectivity index S-1 as well as an SHE assessment.
- Weiss, Markus,Brinkmann, Tobias,Groeger, Harald
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supporting information; experimental part
p. 1580 - 1588
(2010/12/19)
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- Practical, highly enantioselective chemoenzymatic one-pot synthesis of short-chain aliphatic β-amino acid esters
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A practical, highly enantioselective method for the synthesis of short-chain aliphatic β-amino acid esters was developed starting from prochiral and easily accessible substrates. This chemoenzymatic approach is based on a nonenzymatic aza-Michael addition
- Wei?, Markus,Gr?ger, Harald
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experimental part
p. 1251 - 1254
(2009/09/06)
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- Diastereoselective synthesis of α-methyl and α-hydroxy-β- amino acids via 4-substituted-1,3-oxazinan-6-ones
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(Chemical Equation Presented) 1,3-Oxazinan-6-ones have been utilized in a series of enolate reactions to produce 5-hydroxy and 5-alkyl-4-substituted-1,3- oxazinan-6-ones with excellent trans diastereoselectivity. Highlighting the versatility of the oxazin
- Sleebs, Brad E.,Hughes, Andrew B.
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p. 3340 - 3352
(2008/02/08)
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- The directed cleavage of substituted 1-phenylethylamines: A novel route to enantiomerically pure β-amino acid esters and β-lactams
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An efficient novel access to enantiomerically pure β-amino acid esters and β-lactams (e.g., methyl (3S,4S)-1-(tert-butyldimethylsilyl-4-methyl-2-oxoazetidine-3-carboxylat e) from optically active 1-arylethylamines is described. Regiospecific cleavage is performed by Birch reduction and subsequent ozonolysis.
- Bringmann,Geuder
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p. 829 - 831
(2007/10/02)
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