615576-90-4Relevant articles and documents
Design and synthesis of a new generation of 'NH'-Ni(II) complexes of glycine Schiff bases and their unprecedented C-H vs. N-H chemoselectivity in alkyl halide alkylations and Michael addition reactions
Ellis, Trevor K.,Soloshonok, Vadim A.
, p. 533 - 538 (2006)
Within this manuscript the synthesis of a new generation of Ni(II) complexes that contain a secondary rather than a tertiary amino group, as well as the unusual chemoselectivity, was demonstrated in alkyl halide alkylations and Michael addition reactions. The complete C-H chemoselectivity observed in these reactions suggests that coordination of nitrogen to a metal has a significant synthetic potential as protecting a group without the need of introducing a transient N-C substituent. These new complexes have also proven highly synthetically useful nucleophilic glycine equivalents for the simple and highly diastereoselective synthesis of β-substituted pyroglutamic acids via their reactions with chiral Michael acceptors. Georg Thieme Verlag Stuttgart.
Effect of substituents on the configurational stability of the stereogenic nitrogen in metal(II) complexes of α-amino acid Schiff bases
Mei, Haibo,Jean, Marion,Albalat, Muriel,Vanthuyne, Nicolas,Roussel, Christian,Moriwaki, Hiroki,Yin, Zizhen,Han, Jianlin,Soloshonok, Vadim A.
, p. 401 - 409 (2019/04/01)
Herein, we report a general method for quantitative measurement of the configurational stability of the stereogenic nitrogen coordinated to M (II) in the corresponding square planar complexes. This stereochemical approach is quite sensitive to steric and electronic effects of the substituents and shown to work well for Ni(II), Pd(II), and Cu(II) complexes. Structural simplicity of the compounds used, coupled with high sensitivity and reliability of experimental procedures, bodes well for application of this approach in evaluation of chemical stability and stereochemical properties of newly designed chiral ligands for general asymmetric synthesis of tailor-made amino acids.
NH-type of chiral Ni(ii) complexes of glycine Schiff base: Design, structural evaluation, reactivity and synthetic applications
Bergagnini, MacKenzie,Fukushi, Kazunobu,Han, Jianlin,Shibata, Norio,Roussel, Christian,Ellis, Trevor K.,Acena, Jose Luis,Soloshonok, Vadim A.
, p. 1278 - 1291 (2014/03/21)
The work being reported here deals with the design of a new type of "N-H" Ni(ii) complexes of glycine Schiff bases and study general aspects of their reactivity. It was confirmed that the presence of NH function in these Ni(ii) complexes does not interfere with the homologation of the glycine residue, rendering these derivatives of high synthetic value for the general synthesis of α-amino acids. In particular, the practical application of these NH-type complexes was demonstrated by asymmetric synthesis of various-substituted pyroglutamic acids via Michael addition reactions with chiral Michael acceptors.
Substituent-controlled preference of carbonyl group-metal coordination in d8 metal complexes with non-symmetric pentadentate ligands. Structural and stereochemical aspects
Han, Jianlin,Ono, Taizo,Uekusa, Hidehiro,Klika, Karel D.,Soloshonok, Vadim A.
, p. 5375 - 5381 (2014/04/03)
Chirally switchable Ni(ii) and Pd(ii) complexes were synthesized and fully characterized by X-ray crystallography and additionally by spectroscopic means (NMR and MS). The syntheses and characterization of their ligands are also reported. It was found that control of the stereochemical preference between (S*,S*) and (S*,R*) diastereomers by substituent modification of the ligand sidearms was possible in the solid state with the preferred atomic coordinations of the sidearms consistent with expectations based on the electron-withdrawing properties of the substituent -o-CF 3 group. The dilemma arising in terms of assigning the absolute configuration descriptors resulting from selecting between strictly following only the covalent bonds of the ligand and disregarding the nature of the bonds altogether and thus bringing the coordinate bonds into consideration to determine the stereochemical priority sequence is hereby resolved by declaring that the latter option is to be preferred. The results obtained here provide a clear indication that sidearm substitution of the Ni(ii) and Pd(ii) complexes need not disturb macromolecular stereochemical arrangements leading to quasidiastereomeric relationships. This permits the design of molecular systems sensitive to external stimuli with predictable macromolecular structure. This journal is the Partner Organisations 2014.
Highly diastereoselective synthesis of new, carbostyril-based type of conformationally-constrained β-phenylserines
Ueki, Hisanori,Ellis, Trevor K.,Khan, Masood A.,Soloshonok, Vadim A.
, p. 7301 - 7306 (2007/10/03)
We have demonstrated that the readily available amido-keto compounds 5, with prearranged carbonyl and glycine moieties, under strongly basic conditions easily undergo complete and highly diastereoselective cyclization, affording a generalized and practical access to the conformationally constrained phenylserine derivatives 4. High chemical yields, virtually complete diastereoselectivity combined with the operational convenience of the experimental procedures render this method useful for preparation of these diastereomerically pure derivatives.
