171181-53-6Relevant articles and documents
Amino Acid Schiff Base Bearing Benzophenone Imine As a Platform for Highly Congested Unnatural α-Amino Acid Synthesis
Matsumoto, Yohei,Sawamura, Jun,Murata, Yumi,Nishikata, Takashi,Yazaki, Ryo,Ohshima, Takashi
supporting information, p. 8498 - 8505 (2020/05/18)
Unnatural α-amino acids are invaluable building blocks in synthetic organic chemistry and could upgrade the function of peptides. We developed a new mode for catalytic activation of amino acid Schiff bases, serving as a platform for highly congested unnatural α-amino acid synthesis. The redox active copper catalyst enabled efficient cross-coupling to construct contiguous tetrasubstituted carbon centers. The broad functional group compatibility highlights the mildness of the present catalysis. Notably, we achieved successive β-functionalization and oxidation of amino acid Schiff bases to afford dehydroalanine derivatives bearing tetrasubstituted carbon. A three-component cross-coupling reaction of an amino acid Schiff base, alkyl bromides, and styrene derivatives demonstrated the high utility of the present method. The diastereoselective reaction was also achieved using menthol derivatives as a chiral auxiliary, delivering enantiomerically enriched α-amino acid bearing α,β-continuous tetrasubstituted carbon. The synthesized highly congested unnatural α-amino acid could be derivatized and incorporated into peptide synthesis.
Access to α-Arylglycines by Umpolung Carboxylation of Aromatic Imines with Carbon Dioxide
Guo, Chun-Xiao,Zhang, Wen-Zhen,Zhou, Hui,Zhang, Ning,Lu, Xiao-Bing
, p. 17156 - 17159 (2016/11/23)
A straightforward and transition-metal-free approach for the efficient synthesis of α-arylglycine derivatives from aromatic imines and carbon dioxide was enabled by an umpolung carboxylation reaction. Various substituted diphenylmethimines underwent the carboxylation smoothly with carbon dioxide in the presence of potassium tert-butoxide and 18-crown-6 to give the corresponding carboxylated products in good to high yields. Besides the enhancement of the solubility of potassium tert-butoxide in THF, 18-crown-6 also plays key roles in suppressing the reverse protonation or 1, 3-proton shift isomerization as well as by stabilizing the carboxylated intermediate.
Efficient synthesis of functionalized α-aryl α-aminoesters via reaction of polyfunctional diarylzincs with a glycine cation equivalent
Lamaty, Frederic,Lazaro, Rene,Martinez, Jean
, p. 3385 - 3386 (2007/10/03)
Functionalized diarylzine reagents, easily available from the corresponding aryl halides by a halogen-lithium exchange followed by transmetalation with ZnCl2 react with a glycine cation equivalent to afford substituted α-aryl α-amino esters in good yields.
