Nitrile Biotransformations for Highly Efficient and Enantioselective Syntheses of Electrophilic Oxiranecarboxamides
摘要:
Catalyzed by a nitrile hydratase/amidase-containing microbial Rhodococcus sp. AJ270 whole-cell catalyst, a number of racemic trans-2,3-epoxy-3-arylpropanenitriles 1 underwent rapid and efficient hydrolysis under very mild conditions to afford 2R,3S-2-arylglycidamides 2 in excellent yield with enantiomeric excess higher than 99.5%. The overall enantioselectivity of the biotransformations originated from the combined effects of a dominantly high 2S-enantioselective amidase and low 2S-enantioselective nitrile hydratase involved in the cell. The influence of the substrates on both reaction efficiency and enantioselectivity was also discussed in terms of steric and electronic effects.
BF<sub>3</sub>·OEt<sub>2</sub>-promoted tandem Meinwald rearrangement and nucleophilic substitution of oxiranecarbonitriles
作者:Chuangchuang Xu、Jiaxi Xu
DOI:10.1039/c9ob02428j
日期:——
Tandem Meinwald rearrangement and nucleophilicsubstitution of oxiranenitriles was realized. Arylacetic acid derivatives were readily synthesized from 3-aryloxirane-2-carbonitriles with amines, alcohols, or water in the presence of boron trifluoride under microwave irradiation, and the designed synthetic strategy includes introducing a cyano leaving group into arylepoxides and capturing the in situ
Metal-free and regiospecific synthesis of 3-arylindoles
作者:Chuangchuang Xu、Wenlai Xie、Jiaxi Xu
DOI:10.1039/d0ob00317d
日期:——
arylhydrazine hydrochlorides and Fischer indolization. The organic base triethylamine plays a crucial role in the final elimination step in the Fischer indole synthesis, affording 3-arylindoles regiospecifically. The reaction features advantages of microwave acceleration, non-metal participation, short reaction time, organic acid-base co-catalysis, and broad substrate scope.
BF3·OEt2-Catalyzed Synthesis of anti-β-(N-Arylamino)-α-hydroxynitriles by Regio- and Diastereospecific Ring Opening of 3-Aryloxirane-2-carbonitriles with Anilines
作者:Chuangchuang Xu、Yang Lu、Kaini Xu、Jiaxi Xu
DOI:10.1055/s-0039-1690243
日期:2020.2
anti-β-(N-arylamino)-α-hydroxynitriles from 3-aryloxirane-2-carbonitriles and anilines was developed under the catalysis of BF3·OEt2 in ethanol. In this method, BF3·OEt2 first reacts with ethanol to produce the true catalyst of super acid H[B(OEt)F3], followed by an acid-catalyzed regio- and diastereospecific ring opening of oxirane-2-carbonitriles with anilines, generating anti-β-(N-arylamino)-α-hydroxynitriles
Thiourea-Mediated Stereospecific Deoxygenation of Cyanoepoxides to Access Highly Diastereopure Alkenyl Nitriles
作者:Yujie Zhang、Shukui Shi、Zhanhui Yang
DOI:10.1021/acs.joc.3c02869
日期:2024.2.16
A practical and efficient protocol for synthesis of >99% diastereopure Z- and E-alkenyl nitriles is developed, through tetramethylthiourea-mediated stereospecificdeoxygenation of respective cis- and trans-cyanoepoxides in ethanol. The desired products are obtained in excellent yields.