291763-96-7Relevant academic research and scientific papers
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.
Application of modular nucleophilic glycine equivalents for truly practical asymmetric synthesis of β-substituted pyroglutamic acids
Soloshonok, Vadim A.,Ueki, Hisanori,Ellis, Trevor K.,Yamada, Takeshi,Ohfune, Yasufumi
, p. 1107 - 1110 (2007/10/03)
A new series of achiral glycine equivalents have been evaluated with respect to their synthetic utility for the production of β-substituted pyroglutamic acid derivatives. Among them, the piperidine-derived complex was found to be a superior glycine derivative for the Michael additions with various (R)-N-(E-enoyl)-4-phenyl-1,3-oxazolidin-2-ones representing a general and practical synthesis of sterically constrained β-substituted pyroglutamic acids. In particular, application of complex allowed for the first time preparation of the corresponding isopropyl derivatives thus increasing the synthetic efficiency and expanding generality these Michael addition reactions.
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.
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 (2007/10/03)
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
