6070-68-4Relevant academic research and scientific papers
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.
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
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 (2007/10/03)
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.
