New Concepts for Organocatalysis
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Fig. 2. The reaction of isovaleraldehyde with 2-naphthyl N-Boc-imine in the
presence of (S)-proline (20 mol%) in CH 3 CN. a Homogenous reaction mixture after mixing all components. b Reaction mixture after completion of the
reaction (10 h)
sired product had precipitated and could easily be collected by filtration
(Fig. 2b).
The N-Boc-imine-derived Mannich products can readily be converted
into the corresponding α,β-branched-β-amino acids (β
2,3 -amino acids).
For example, oxidation of the product 1 to the carboxylic acid followed
by acid-mediated deprotection provided the amino acid salt 2 without
Scheme 9. Conversion of the Mannich product 1 to β-amino acid 2
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Fig. 2. The reaction of isovaleraldehyde with 2-naphthyl N-Boc-imine in the
presence of (S)-proline (20 mol%) in CH 3 CN. a Homogenous reaction mixture after mixing all components. b Reaction mixture after completion of the
reaction (10 h)
sired product had precipitated and could easily be collected by filtration
(Fig. 2b).
The N-Boc-imine-derived Mannich products can readily be converted
into the corresponding α,β-branched-β-amino acids (β
2,3 -amino acids).
For example, oxidation of the product 1 to the carboxylic acid followed
by acid-mediated deprotection provided the amino acid salt 2 without
Scheme 9. Conversion of the Mannich product 1 to β-amino acid 2