6485-52-5Relevant articles and documents
Hybrid catalysis of 8-quinolinecarboxaldehyde and br?nsted acid for efficient racemization of α-amino amides and its application in chemoenzymatic dynamic kinetic resolution
Kiyokawa, Mari,Nagato, Yuya,Ohmatsu, Kohsuke,Ooi, Takashi,Shirai, Yuto
, (2021/06/21)
The combination of 8-quinolinecarboxaldehyde and benzoic acid proved to be an effective catalyst system for the racemization of N-unprotected α-aryl- or α-alkyl-substituted α-amino amides. Application of this system to chemoenzymatic dynamic kinetic resolution provided an efficient access to enantiomerically pure N-acetyl-α-amino amides in good to high yields.
Highly Active Chiral Dilithium(I) Binaphthyldisulfonate Catalysts for Enantio- And Chemoselective Strecker-Type Reactions
Hatano, Manabu,Nishio, Kosuke,Mochizuki, Takuya,Nishikawa, Keisuke,Ishihara, Kazuaki
, p. 8178 - 8186 (2019/08/22)
An enantioselective Strecker-type reaction of aldimines and ketimines was developed by using a chiral dilithium(I) binaphthyldisulfonate as a chiral acid-base cooperative catalyst. The present catalytic system features an extremely short reaction time (10 min to 4 h), unlike conventional catalytic systems. Along with the design of stronger chiral Li(I) Lewis acid catalysts, a highly reactive pentacoordinate silicate generated in situ could promote the reactions. In particular, instead of unstable N-Bn Strecker products, more stable N-CH2(9-anthryl) and N-CH2(1-naphthyl) Strecker products could be obtained in high yields with high enantioselectivities. By a switch of the present and previous catalyst systems, chemoselective cyanation to a ketoaldimine could be performed, respectively. Moreover, mechanistic investigations provided useful information regarding the active catalysts, catalytic cycles, and possible transition states.
RETRACTED ARTICLE: Chemoenzymatic Method for Enantioselective Synthesis of (R)-2-Phenylglycine and (R)-2-Phenylglycine Amide from Benzaldehyde and KCN Using Difference of Enzyme Affinity to the Enantiomers
Kawahara, Nobuhiro,Asano, Yasuhisa
, p. 5014 - 5020 (2018/10/20)
In general, enzymatic and chemoenzymatic methods for asymmetric synthesis of α-amino acids are performed using highly enantioselective enzymes. The enzymatic reactions using α-aminonitrile as a starting material have been performed using reaction conditions apart from the chemical Strecker synthesis. We developed a new chemoenzymatic method for the asymmetric synthesis of α-amino acids from aldehydes and KCN by performing Strecker synthesis and nitrilase reaction in the same reaction mixture. Nitrilase AY487533 that showed rather low enantioselectivity in hydrolysis of 2-phenylglycinonitrile (2PGN) to 2-phenylglycine (2PG) was utilized in the hydrolysis of aminonitrile formed from benzaldehyde and KCN via 2PGN by Strecker synthesis, preferentially synthesizing (R)-2PG with more than 95 % yield and enantiomeric excess (ee). The method was also utilized for the synthesis of (R)-2-phenylglycine amide ((R)-2PGNH2) from benzaldehyde and KCN by the chemoenzymatic reaction in the presence of a mutated nitrilase AY487533W186A, which catalyzes the conversion of 2PGN to 2PGNH2.
