78761-22-5Relevant academic research and scientific papers
Enantiospecific alkylations of alanine
Alonso, Francisco,Davies, Stephen G.,Elend, Almut S.,Haggitt, Jane L.
, p. 257 - 264 (2007/10/03)
Reaction of ferrocenecarbaldehyde 3 with sodium (S)-alaninate followed by pivaloyl chloride generates (2S,4S)-2-ferrocenyl-3-pivaloyl-4-methyl-1,3-oxazolidin-5-one 5 (>98% de). Compound 5 undergoes stereospecific 4-alkylation with complete retention of configuration on treatment sequentially with lithium diisopropylamide and an appropriate alkyl bromide {benzyl bromide, allyl bromide, crotyl [(E)-2-enyl] bromide, α-bromo-o-xylene, cinnamyl bromide, 2-(bromomethyl)naphthalene, 1-(tert-butoxycarbonyl)-3-(bromomethyl)indole and bromoacetonitrile} to generate the corresponding (2S,4R)-2-ferrocenyl-3-pivaloyl-4-alkyl-4-methyl-1,3-oxazolidin-5-ones 7a-h. Hydrolysis of (2S,4R)-7a-h on Amberlyst-15 generates the free (R)-α-methyl-α-amino acids (R)-8a-h.
ASYMMETRIC SYNTHESIS OF α-ALKYLATED α-AMINO ACIDS VIA SCHMIDT REARRANGEMENT OF α,α-BISALKYLATED β-KETO ESTERS
Georg, Gunda I.,Guan, Xiangming,Kant, Joydeep
, p. 403 - 406 (2007/10/02)
α-Alkylated α-amino acids are obtained in high yield and optical purity through Schmidt rearrangement of optically active α,α-bisalkylated β-keto esters.
Asymmetric Syntheses via Heterocyclic Intermediates, V. - Asymmetric Synthesis of α-Methyl Amino Acids by Alkylation of the Lithiated Lactim Ether of cyclo-(L-Ala-L-Ala)
Schoellkopf, Ulrich,Hartwig, Wolfgang,Groth, Ulrich,Westphalen, Karl-Otto
, p. 696 - 708 (2007/10/02)
The (3S,6S)-2,5-dimethoxy-3,6-dimethyl-3,6-dihydropyrazine (7) is obtained from cyclo-(L-Ala-L-Ala) 5 (93-95percent optically pure) and trimethyloxonium tetrafluoroborate.With butyllithium the lithio derivative 8 is formed which reacts with alkyl halides in good chemical yields and with more than 90percent diastereoselectivity, whereby R-configuration is induced at C-3.A model concept is discussed, which explains the remarkably high asymmetric induction. - Hydrolysis (0.25 N HCl, room temp.) gives L-alanine methyl ester (4) and the (R)-α-methyl amino acid methyl esters 13.The two amino acid esters are separable by distillation or chromatography.
