Group-Assisted Purification (GAP) for Protection of Amino Acids Using N-Phosphonyl Functional Groups
摘要:
Various phosphonyl halides have been synthesized and utilized as protection groups for amino acids. The protection synthesis was performed via GAP (Group-Assisted Purification) procedure under convenient conditions without the use of column chromatography and recrystallization. The synthesis can be carried out on applicational scales with excellent yields (82% - 98%). The phosphonyl protection of amino acids would provide a new greener tool for GAP peptide synthesis.
Asymmetric allylation reactions of aromatic aldehydes with allyltrichlorosilane catalyzed by chiral bisformamide-type organocatalysts
作者:Yuya Tanimura、Kaori Ishimaru
DOI:10.1016/j.tetasy.2012.02.015
日期:2012.3
Asymmetricallylation reactions of aromatic aldehydes with allyltrichlorosilane were catalyzed by C2-symmetrical chiral bisformamides in the presence of potassium carbonate and potassium phosphate, to afford the corresponding homoallylic alcohols in excellent yields with up to 83% ee.
In non-racemic (1R,2R)-(1,2-dialkyl)-1,2-diaminocyclohexane palladium dichloride complexes the C2 symmetry of the diamine ligand is broken, resulting in selective R,S-coordination.
A series of N,N′-dialkylated derivatives of (1R,2R)-cyclohexane-1,2-diamine were synthesized, and a new approach to the one-pot preparation of this type of amine was demonstrated. The prepared diamines were used as organocatalysts for the two-stepsynthesis of α-hydroxy γ-keto esters from arenes, chlorooxoacetates, and ketones; they were also used as chiral ligands for Meervein–Ponndorf–Verley reductions
HFIP‐Promoted Substitution in the Ferrocene Series: Smooth Approach towards Original Catalysts**
作者:William Erb、Victor Carré、Thierry Roisnel
DOI:10.1002/ejoc.202100824
日期:2021.11.8
Pseudo-benzylic substitution promoted by fluorinated solventfrom various iodoferrocenes is described. These new reaction conditions allow the fast generation of libraries of derivatives for applications in catalysis for example, as demonstrated with the synthesis of original ligands used in cross-coupling reactions.
Nickel-Catalyzed Asymmetric <i>C</i>-Alkylation of Nitroalkanes: Synthesis of Enantioenriched β-Nitroamides
作者:Vijayarajan Devannah、Rajgopal Sharma、Donald A. Watson
DOI:10.1021/jacs.9b04175
日期:2019.5.29
A general catalytic method for asymmetric C-alkylation of nitroalkanes using nickel catalysis is described. This method enables the formation of highly enantioenriched β-nitroamides from readily available α-bromoamides using mild reaction conditions that are compatible with a wide range of functional groups. When combined with subsequent reactions, this method allows access to highly enantioenriched