246232-25-7Relevant academic research and scientific papers
Michael addition reactions between chiral equivalents of a nucleophilic glycine and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3-oxazolidin-2-ones as a general method for efficient preparation of β-substituted pyroglutamic acids. Case of topographically control
Soloshonok, Vadim A.,Cai, Chaozhong,Yamada, Takeshi,Ueki, Hisanori,Ohfune, Yasufumi,Hruby, Victor J.
, p. 15296 - 15303 (2005)
This paper describes a systematic study of addition reactions between the chiral Ni(II) complex of the Schiff base of glycine with (S)-o[N-(N- benzylprolyl)amino]benzophenone and (S)- or (R)-3-[(E)-enoyl]-4-phenyl-1,3- oxazolidin-2-ones as a general and s
Asymmetric Michael addition reactions of chiral Ni(II)-complex of glycine with (N-trans-enoyl)oxazolidines: Improved reactivity and stereochemical outcome
Soloshonok, Vadim A.,Cai, Chaozhong,Hruby, Victor J.
, p. 4265 - 4269 (1999)
Application of the (N-trans-enoyl)oxazolidines as Michael acceptors in the kinetically controlled additions with a Ni(II)-complex of the chiral Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)amino]benzophenone 1 was shown to be synthetically advantageous over the alkyl enoylates, allowing for remarkable improvement in reactivity and, in most cases, diastereoselectivity of the reactions. While the stereochemical outcome of the Michael additions of the aliphatic (N-trans-enoyl)oxazolidines with complex 1 depended on the steric bulk of the alkyl group on the starting oxazolidines, the diastereoselectivity of the aromatic (N-trans-enoyl)oxazolidines reactions was found to be controlled by the electronic properties of the aryl ring. In particular, the additions of complex 1 with (N-cinnamoyl)oxazolidines, bearing electron-withdrawing substituents on the phenyl ring, afforded the (2S,3R)-configured products with synthetically useful selectivity and in quantitative chemical yield, thus allowing an efficient access to sterically constrained β-substituted pyroglutamic acids and related compounds. (C) 1999 Elsevier Science Ltd.
A practical asymmetric synthesis of enantiomerically pure 3-substituted pyroglutamic acids and related compounds
Soloshonok, Vadim A.,Cai, Chaozhong,Hruby, Victor J.
, p. 2172 - 2175 (2000)
DBU-catalyzed Michael addition reactions were shown to occur at room temperature between a nickel(II) complex of the Schiff base of glycine 1 and (S)- or (R)-N-(E-enoyl)-4-phenyl-3-oxazolidin-2-ones (2, see scheme). This reaction, which has an almost comp
Application of (S)- and (R)-methyl pyroglutamates as inexpensive, yet highly efficient chiral auxiliaries in the asymmetric Michael addition reactions
Cai, Chaozhong,Yamada, Takeshi,Tiwari, Rohit,Hruby, Victor J.,Soloshonok, Vadim A.
, p. 6855 - 6858 (2004)
Methyl N-(E-enoyl)pyroglutamates, derived from inexpensive and readily available in both enantiomeric forms pyroglutamic acid were found to be an efficient Michael acceptors in the addition reactions with nucleophilic glycine equivalent allowing for an ef
Michael addition reactions between various nucleophilic glycine equivalents and (S,E)-1-enoyl-5-oxo-N-phenylpyrrolidine-2-carboxamide, an optimal type of chiral Michael acceptor in the asymmetric synthesis of β-phenyl pyroglutamic acid and related compoun
Ellis, Trevor K.,Ueki, Hisanori,Tiwari, Rohit,Soloshonok, Vadim A.
scheme or table, p. 2629 - 2634 (2010/03/25)
(S)-5-Oxo-N-phenyl-1-[(E)-3-phenylacryloyl]pyrrolidine-2-carboxamide, easily prepared from inexpensive and readily available, in both enantiomeric forms, glutamic/pyroglutamic acid was designed as an optimal type of chiral Michael acceptor for reactions w
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 (2007/10/03)
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.
Virtually complete control of simple and face diastereoselectivity in the Michael addition reactions between achiral equivalents of a nucleophilic glycine and (S)- or (R)-3-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones: Practical method for preparation of β-substituted pyroglutamic acids and prolines
Soloshonok, Vadim A.,Ueki, Hisanori,Tiwari, Rohit,Cai, Chaozhong,Hruby, Victor J.
, p. 4984 - 4990 (2007/10/03)
This study demonstrates a new strategy for controlling the stereochemical outcome of the Michael addition reactions between nucleophilic glycine equivalents and α,β-unsaturated carboxylic acid derivatives: The addition reactions between achiral Ni(II)-complex of the Schiff base of glycine with o-[N-α-pycolylamino]acetophenone and (S)- or (R)-3-(E-enoyl)-4- phenyl-1,3-oxazolidin-2-ones were shown to occur at room temperature in the presence of nonchelating organic bases and, most notably, with very high stereoselectivity at both newly formed stereogenic centers. Thus, the chiral 4-phenyl-1,3-oxazolidin-2-one moiety was found to control efficiently both face diastereoselectivities of the glycine derived enolate and the C,C double bond of the Michael acceptor. The new strategy developed in this work is methodologically superior to previous methods, most notably in terms of generality and synthetic efficiency. Excellent chemical yields and diastereoselectivities, combined with the simplicity of the experimental procedures, render the present method of immediate use for preparing various 3-substituted pyroglutamic acids and related amino acids (glutamic acids, glutamines, prolines, etc.) available via conventional transformations of the former.
Michael addition reactions between chiral Ni(II) complex of glycine and 3-(trans-enoyl)oxazolidin-2-ones. A case of electron donor - Acceptor attractive interaction-controlled face diastereoselectivity
Cai,Soloshonok,Hruby
, p. 1339 - 1350 (2007/10/03)
This study has demonstrated that the readily available and inexpensive 3-(trans-3′-alkyl/arylpropenoyl)oxazolidin-2-ones, featuring high electrophilicity and conformational homogeneity, are synthetically superior Michael acceptors over the conventionally used alkyl enoylates, allowing for a remarkable improvement in reactivity and, in most cases, diastereoselectivity of the addition reactions with a Ni(II) complex of the chiral Schiff base of glycine with (S)-o-[N-(N-benzylprolyl)-amino]benzophenone. Kinetically controlled diastereoselectivity in the corresponding Michael addition reactions between the Ni(II) complex of glycine and the oxazolidin-2-ones was systematically studied as a function of steric, electronic, and position effects of the substituents on the starting Michael acceptor. In both aliphatic and aromatic series the simple diastereoselectivity was found to be virtually complete, affording the products via the corresponding TSs with the approach geometry like. The face diastereoselectivity of the reactions between the Ni(II) complex of glycine and the 3-(trans-3′-alkylpropenoyl)oxazolidin-2-ones was found to depend exclusively on the steric bulk of the alkyl group on the starting Michael acceptor. In contrast, the face diastereoselectivity in the reactions of aromatic oxazolidin-2-ones with the Ni(II) complex of glycine was shown to be controlled predominantly by the electronic properties of the aryl ring. In particular, the additions of the Ni(II) complex of glycine with 3-(trans-3′-arylpropenoyl)oxazolidin-2-ones, bearing electron-withdrawing substituents on the phenyl ring, afforded the (2S,3R)-configured products with synthetically useful diastereoselectivity and in quantitative chemical yields, thus allowing for an efficient access to the sterically constrained β-aryl-substituted pyroglutamic and glutamic acids.
Stereoselective Michael addition of glycine anions to chiral fischer alkenylcarbene complexes. Asymmetric synthesis of β-substituted glutamic acids
Ezquerra, Jesus,Pedregal, Concepcion,Merino, Isabel,Florez, Josefa,Barluenga, Jose,Garcia-Granda, Santiago,Llorca, Maria-Amparo
, p. 6554 - 6565 (2007/10/03)
The reaction of lithium enolates of achiral N-protected glycine esters with chiral alkoxyalkenylcarbene complexes of chromium provided the corresponding Michael adducts with either high anti or syn selectivity depending on the nature of the nitrogen protecting group, and high diastereofacial selectivity when carbene complexes containing the (-)-8- phenylmenthyloxy group were employed. subsequent oxidation of the metal- carbene moiety followed by deprotection of the amine group and hydrolysis of both carboxylic esters afforded enantiomerically enriched 3-substituted glutamic acids of natural as well as unnatural stereochemistry. Alternatively, when the deprotection step was performed previously to the oxidation, cyclic aminocarbene complexes were formed, which finally led to optically active 3-substituted pyroglutamic acids.
