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Asymmetric Strecker Synthesis of the Four α‐Quaternary 1‐Amino‐2‐methylcyclohexanecarboxylic Acids
Author(s) -
Volk FranzJosef,
Frahm August Wilhelm
Publication year - 1996
Publication title -
liebigs annalen
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.825
H-Index - 155
eISSN - 1099-0690
pISSN - 0947-3440
DOI - 10.1002/jlac.199619961126
Subject(s) - strecker amino acid synthesis , chemistry , steric effects , diastereomer , hydrolysis , amino acid , hexane , high performance liquid chromatography , organic chemistry , stereochemistry , medicinal chemistry , enantioselective synthesis , catalysis , biochemistry
The synthesis of the four 1‐amino‐2‐methylcyclohexanecarboxylic acids 13, 14, 15 , and 16 from diastereomeric mixtures of the α‐amino nitriles 1–4 by successive application of conc. H 2 SO 4 , Pd/C H 2 , and conc. HCl is described. The amino nitriles 1–4 were prepared by asymmetric Strecker synthesis under various reactions, The formation of 1–4 is thermodynamically controlled in protic solvents (e.g. MeOH), whereas the reaction is under kinetic control in non‐protic solvents (e.g. hexane), The separation of the α‐amino amides 5–8 , which were obtained by partial hydrolysis of 1–4 , was achieved by CC, LPLC, and HPLC. The absolute configuration of all synthesized compounds was determined by means of only two X‐ray analyses with consecutive correlations. The steric control of the asymmetric Strecker synthesis is discussed.