97550-62-4Relevant academic research and scientific papers
2,8'-Disubstituted-1,1'-Binaphthyls: A New Pattern in Chiral Ligands
Vyskocil, Stepan,Meca, Ludek,Tislerova, Iva,Cisarova, Ivana,Polasek, Miroslav,Harutyunyan, Syuzanna R.,Belokon, Yuri N.,Stead, Russel M. J.,Farrugia, Louis,Lockhart, Stephen C.,Mitchell, William L.,Kocovsky, Pavel
, p. 4633 - 4648 (2002)
The title binaphthyls 19 and 26, which are the positional isomers of 2-methoxy-2'-(diphenylphosphino)-1,1'-binaphthyl (MOP, 19) and 2-amino-2'-hydroxy-1,1'-binaphthyl (NOBIN, 26), have been synthesized by Suzuki coupling as the key step (10 + 15 -> 18), followed by functional group transformations, involving C-P and C-N bond formation (18 -> 19 and 18 -> 23). Racemic intermediate 22 was resolved by cocrystallization with N-benzylcinchonidinium chloride and the absolute configuration determined by X-ray crystallography. These novel binaphthyls are configurationally stable and, as such, potentially usable as chiral ligands in asymmetric reactions. Michael addition of the glycine-derived enolate 40 to methyl acrylate, carried out in the presence of (R)-(-)-27 as the chiral phase-transfer catalyst, afforded L-glutamic acid (S)-(+)-43 of 92% ee (after hydrolysis of the primary product).
The first example of asymmetric Michael reaction catalyzed by chiral alkali metal alkoxides
Belokon',Kochetkov,Churkina,Chesnokov,Smirnov,Ikonnikov,Orlova
, p. 74 - 81 (2007/10/03)
Some chiral sodium alkoxides can be used as catalysts in the asymmetric Michael reaction as exemplified by the 1,4-addition of an achiral NiII complex of the Schiff base derived from glycine and N-(2-pyridylcarbonyl)-o-aminobenzophenone (1) to
Synthesis of Enantio- and Diastereo-isomerically Pure β- and γ-Substituted Glutamic Acids via Glycine Condensation with Activated Olefins
Belokon, Yuri N.,Bulychev, Aleksandr G.,Ryzhov, Mikhail G.,Vitt, Sergei V.,Batsanov, Andrei S.,et al.
, p. 1865 - 1872 (2007/10/02)
The glycine fragment in the nickel(II) complex formed from the Schiff base of glycine and (S)-o-benzophenone undergoes base-catalysed Michael addition in methanol in the presence of MeONa to the activated olefins methyl acrylate, acrylonitrile, methyl methacrylate, acrolein, and methyl trans-cinnamate.Complexes of substituted (S)-glutamic acid or its derivatives were formed in good chemical yields with almost complete diastereoselection at the α-carbon atom of the amino acid moiety.Diastereoselection at the β- and γ-atoms was not significant, but the isomeric complexes could be easily separated chromatogrphically.Cleavage of the pure diastereoisomers with aqueous HCl gave, in good yields, optically pure glutamic acids and regenerated the original chiral reagent.The configurations of the amino acid β- and γ-carbon atoms were determined by 1H n. m. r. spectroscopy and crystal structure X-ray analysis of the corresponding original complexes.The addition to acrolein, catalysed by triethylamine in methanol, leads to the 1,4-adduct exclusively.The amino acid thus obtained could be converted into (S)-proline by reduction with NaBH4.
