A Convenient Conversion of <i>α</i>-Aminoacids into NH-Boc Protected <i>α</i>-Aminoketones <i>via</i> Imidazolides
作者:Bianca F. Bonini、Mauro Comes-Franchini、Mariafrancesca Fochi、Germana Mazzanti、Alfredo Ricci、Greta Varchi
DOI:10.1055/s-1998-1831
日期:1998.9
Imidazolides obtained from natural α-aminoacids react with a twofold excess of Grignard reagents to afford in satisfactory to good yields the corresponding NH-Boc protected α-aminoketones. Under optimized conditions the reaction with phenyl- and n-pentylmagnesium bromide required the addition of catalytic amounts of Cu(I)-salt which turned out to be unnecessary in the case of Buchi's Grignard.
Zr-Catalyzed Synthesis of Tetrasubstituted 1,3-Diacylpyrroles from <i>N</i>-Acyl α-Aminoaldehydes and 1,3-Dicarbonyls
作者:Caria Evans、William J. Berkey、Christopher W. Jones、Stefan France
DOI:10.1021/acs.joc.3c00675
日期:2023.7.7
3-diacylpyrroles is reported that employs the direct use of N-acyl α-aminoaldehydes with 1,3-dicarbonyl compounds. The products were formed in up to 88% yield and shown to be hydrolytically and configurationally stable under the reaction conditions (THF/1,4-dioxane and H2O). The N-acyl α-aminoaldehydes were readily prepared from the corresponding α-amino acids. The reaction tolerates a wide array of substrate
Stereoselective Three-Carbon and Two-Carbon Elongation of the Carbon Chain in <i>N</i>-Boc-Protected α-Aminoacylsilanes: An Entry to Functionalized β-Amino Alcohols and to Statine Analogues
N-Protected α-amino acids can be easily converted directly into chiral α-amino aldehydes in a one-pot procedure by activation with CDI followed by reduction with DIBAL-H.
3R,4S)-dolaproine and (S)-dolaphenine. Our efficient synthesis includes the following three key features: 1) SmI2-induced cross-coupling was employed to couple aldehyde 11 with (S)-N-tert-butanesulfinyl imine 12 to generate the required stereocenters of Dap (7); 2) Asymmetric addition of chiral N-sulfinyl imine 10 provided a straightforward approach to protected Doe ((S,S)-8); 3) A practical method to