Synthesis of α,α-Disubstituted Unnatural Amino Acid Derivatives Using the Aza[2,3]Wittig Sigmatropic Rearrangement.

ChemInform ◽  
2003 ◽  
Vol 34 (20) ◽  
Author(s):  
James C. Anderson ◽  
Sarah Skerratt
Keyword(s):  
Amino Acid ◽  
Unnatural Amino Acid ◽  
Sigmatropic Rearrangement ◽  
Amino Acid Derivatives

scholarly journals Additive and Emergent Catalytic Properties of Dimeric Unnatural Amino Acid Derivatives: Aldol and Conjugate Additions

2021 ◽  
Author(s):  
Fernando P. Cossío ◽  
María de Gracia Retamosa ◽  
Andrea Ruiz-Olalla ◽  
Maddalen Agirre ◽  
Abel de Cózar ◽  
...  
Keyword(s):  
Amino Acid ◽  
Catalytic Properties ◽  
Unnatural Amino Acid ◽  
Amino Acid Derivatives ◽  
Conjugate Additions

scholarly journals Exploring the Scope of Tandem Palladium and Isothiourea Relay Catalysis for the Synthesis of α-Amino Acid Derivatives

Molecules ◽  
2020 ◽  
Vol 25 (10) ◽  
pp. 2463
Author(s):  
Jacqueline Bitai ◽  
Alexandra M. Z. Slawin ◽  
David B. Cordes ◽  
Andrew D. Smith
Keyword(s):  
Amino Acid ◽  
Transition State ◽  
Quaternary Ammonium ◽  
Palladium Catalyst ◽  
Quaternary Ammonium Salts ◽  
Sigmatropic Rearrangement ◽  
Ammonium Salts ◽  
Amino Acid Derivatives ◽  
Substitution Pattern

The scope and limitations of a tandem N-allylation/[2,3]-rearrangement protocol are investigated through the incorporation of a variety of functional groups within an allylic phosphate precursor. This method uses readily accessible N,N-dimethylglycine aryl esters and functionalized allylic phosphates, forming quaternary ammonium salts in situ in the presence of a palladium catalyst. Subsequent enantioselective [2,3]-sigmatropic rearrangement, promoted by the chiral isothiourea tetramisole, generates α-amino acid derivatives with two contiguous stereocenters. The incorporation of electron-withdrawing ester and amide groups gave the best results, furnishing the desired products in moderate to good yields (29–70%), with low diastereocontrol (typically 60:40 dr) but high enantioselectivity (up to 90:10 er). These results indicate that substrate–catalyst interactions in the proposed transition state are sensitive to the substitution pattern of the substrates.

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