149775-93-9Relevant academic research and scientific papers
Reduction of 4-Oxo-α-Amino Acids as a Route to 4-Hydroxylated α-Amino Acids. Concise Approaches to the Synthesis of Clavalanine, erythro-4-Hydroxyornithine and (+)-Bulgecinine
Jackson, Richard F. W.,Rettie, Alan B.,Wood, Anthony,Withes, Martin J.
, p. 1719 - 1726 (2007/10/02)
The stereochemical course of reduction of derivatives of 4-oxo-α-amino acids 3 to give cis- and trans-γ-substituted α-aminobutano-4-lactones 9 and 10 using a range of hydride reducing agents is reported.Athough reduction with sodium boranuide (sodium borohydride) in protic solvents proceeds with low stereoselectivity, use of triethylsilane-boron trifluoride-diethyl ether gives good selectivity in favour of the cis-isomer, provided that the 4-substituent is phenyl.Moderate to excellent stereoselectivity in favour of the trans-isomer may be obtained by using L-Selectride in tetrahydrofuran.The presence of an additional stereogenic centre at C-5 completely overwhelms the effect of the α-centre.Applications of this method in approaches to the synthesis of clavalanine, erythro-4-hydroxyornithine and (+)-bulgecinine are described.
Short, stereoselective syntheses of 4,5,6-trihydroxylated norleucines: An approach to the synthesis of (+)-bulgecinine
Jackson,Rettie
, p. 2985 - 2986 (2007/10/02)
Reaction of the L-serine derived zinc reagent 1 with D-isopropylideneglyceryl chloride gave the 4-oxo amino acid 5, which was reduced with high diastereoselectivity to give the trans-lactone 7. Analogous reaction of the D-serine derived zinc reagent gave the the 4-oxo amino acid 6, which was reduced with high diastereoselectivity to give the cis-lactone 8. Conversion of 8 to 11, the enantiomer of the Box-protected analogue 10 of an intermediate in Fleet's synthesis of (-)-bulgecinine, was achieved in two steps.
