149118-38-7Relevant academic research and scientific papers
Palladium-catalyzed asymmetric decarboxylative allylation of azlactone enol carbonates: Fast access to enantioenriched α-allyl quaternary amino acids
Serra, Massimo,Bernardi, Eric,Marrubini, Giorgio,De Lorenzi, Ersilia,Colombo, Lino
, p. 732 - 741 (2019/01/09)
We report a fast protocol for the synthesis of enantioenriched quaternary 4-allyl oxazol-5-ones. The key step is a Pd-catalyzed enantioselective Tsuji allylation of azlactone allyl enol carbonates, which can be easily prepared starting from racemic α-amino acids. The use of (R,R)-DACH-phenyl Trost chiral ligand allowed the attainment of the allylated derivatives in very good yields (83–98 %) and with ee up to 85 %. Scaling up the allylation protocol to gram quantities did not affect the yields end ee values. The produced 4-allyl azlactones can be converted into the corresponding quaternary amino acids or submitted to further synthetic elaborations exploiting the allyl moiety as a handle for the attachment of alkyl and aryl groups. After hydrolysis of the azlactone ring, the zwitterionic amino acids can be attained in enantiopure or nearly optically pure form through only one recrystallization step.
Enzymatic resolution of α,α-disubstituted α-amino acid esters and amides
Kaptein,Boesten,Broxterman,Peters,Schoemaker,Kamphuis
, p. 1113 - 1116 (2007/10/02)
The scope and limitations of the enzymatic resolution of α,α-disubstituted α-amino acid amides by an amino acid amidase from Mycobacterium neoaurum and of the corresponding ethyl esters with Pig liver esterase (PLE) have been studied. Moderate enantiomeric excesses were obtained with PLE, with only a narrow substrate specificity. Mycobacterium neoaurum on the contrary yields a broad range of S-α,α-disubstituted α-amino acids 1 and the corresponding R-amides 2.
