Indium–Silver- and Zinc–Silver-Mediated Barbier–Grignard-Type Alkylation Reactions of Imines by Using Unactivated Alkyl Halides in Aqueous Media
作者:Zhi-Liang Shen、Hao-Lun Cheong、Teck-Peng Loh
DOI:10.1002/chem.200701468
日期:2008.2.18
efficient and practical method for the Barbier-Grignard-typealkylationreactions of simple imines by using a one-pot condensation of various aldehydes, amines (including the aliphatic and chiral version), and secondary alkyl iodides has been developed. The reaction proceeded more efficiently in water than in organic solvents. Without the use of CuI, it mainly gave the imine self-reductive coupling product
Facile Synthesis of β-Amino
Disulfides, Cystines, and Their Direct Incorporation into
Peptides
作者:Srinivasan Chandrasekaran、Nasir Baig R. B.、Catherine Kanimozhi、V. Sai Sudhir
DOI:10.1055/s-0028-1088133
日期:——
the synthesis of beta-amino disulfides by regioselectiveringopening of sulfamidates with benzyltriethylammonium tetrathiomolybdate [BnNEt3](2)MoS4. Stability and reactivity of different protecting groups under the reaction conditions have been discussed. This methodology has also been extended to serine and threonine derived sulfamidates to furnish cystine and 3,3'-dimethyl cystine derivatives.
A microwave-assisted tandem [3+2] cycloaddition/retro-Diels–Alder reaction of azomethine ylides derived from imines of α-aminoesters to dimethyl 7-oxabicyclo[2.2.1]hepta-2,5-diene-2,3-dicarboxylate derivatives is described. The procedure delivers, in a short reaction time, pyrrolines in high yields. In a such sequence, the oxanorbornadiene derivatives behave as masked forms of dimethyl acetylenedicarboxylate
Copper-Catalyzed Enantioselective Difluoromethylation of Amino Acids via Difluorocarbene
作者:Lingzi Peng、Hongyi Wang、Chang Guo
DOI:10.1021/jacs.1c02697
日期:2021.5.5
of amino esters into corresponding valuable DFAA products in good yields with excellent enantioselectivities. This denovosynthesis creates opportunities to integrate an asymmetric catalytic platform for the preparation of diverse libraries of biologically important DFAA derivatives and will support efforts in both drug discovery and development.
Zinc-mediated Coupling Reaction of 2-Bromo-2,3,3,3-tetrafluoropropanoate with Various Chiral Imines. Simple and Effective Access to Optically Active α-Fluoro-α-(trifluoromethyl)-β-amino Esters
The reactions of benzyl 2-bromo-2,3,3,3-tetrafluoropropanoate with various types of chiral imines in the presence of zinc in THF at room temperature were revealed to afford the threo- and erythro-isomers of α-fluoro-α-(trifluoromethyl)-β-amino esters with high diasteremeric excesses in fair to good chemical yields.