Synthesis of α-Amino Acids and Derivatives
A Zn/Cu(OTf)2-mediated addition of alkyl bromides to dehydroalanine (Dha) derivatives including dipeptides and tripeptides provides selective and biocompatible access to various amino acid units in good to high yields in an aqueous medium.
J.-A. Shin, J. Kim, H. Lee, S. Ha, H.-Y. Lee, J. Org. Chem., 2019, 84, 4558-4565.
Rhodium-catalyzed conjugate addition of potassium trifluoro(organo)borates to dehydroalanine derivatives, using chiral ligands such as fluorophos and in situ enantioselective protonation with guaiacol (2-methoxyphenol), afforded a variety of protected α-amino esters with high yields and enantiomeric excesses up to 95%.
L. Navarre, R. Martinez, J.-P. Genet, S. Darses, J. Am. Chem. Soc., 2008, 130, 6159-6169.
Potassium trifluoro(organo)borates, which are highly stable and easily prepared organoboron derivatives, were able to react with various dehydroamino esters to alanine derivatives in good to high yields. This reaction, catalyzed by rhodium complexes, tolerates a great variety of amino protecting groups.
L. Navarre, S. Darses, J.-P. Genet, Eur. J. Org. Chem., 2004, 69-73.