Abstract
The group-assisted purification asymmetric synthesis of α,β-diamino acid derivatives was achieved by treating chiral N-phosphonyl imines with a NiII-complexed glycine-derived enolate; traditional purification techniques such as chromatography and recrystallization are not required. Successful control of the syn stereochemistry of the vicinal diamino products complements our previous methods that afforded anti stereoisomers; thus, all four individual isomers can be synthesized simply by changing the geometry of the enolate. In contrast to our previous synthesis in which at least 5 equiv. of the glycine Schiff base enolate was required for complete conversion, the new synthesis only needs 1.1 equiv. of the glycine Schiff base enolate to give complete diastereoselectivity (>30:1 dr) and high yields (91-97 %). The absolute stereochemistry was unambiguously determined by X-ray structure analysis.
Original language | English |
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Pages (from-to) | 4744-4747 |
Number of pages | 4 |
Journal | European Journal of Organic Chemistry |
Issue number | 22 |
DOIs | |
State | Published - Aug 2013 |
Keywords
- Amino acids
- Asymmetric synthesis
- Nickel
- Phosphorus
- Schiff bases