202. Stereoselective deconjugation of macrocyclic α,β-unsaturated esters by sequential amidation and olefin transposition: application to enantioselective phase-transfer catalysis
     Alexandre Homberg, Radim Hrdina, Mahesh Vishe, Laure Guénée, Jérôme Lacour
     Org. Biomol. Chem. 2019, 17, 6905-6910

The stereoselective synthesis of chiral macrocycles bearing two aliphatic amide functional groups is reported. After the amidation mediated by TBD, a guanidine derivative, the olefin transposition step is performed with a slight excess of t-BuOK. The products are afforded in moderate to good combined yields (up to 59%) and with an excellent syn diastereoselectivity (dr > 49:1). Introducing enantiopure α-branched substituents was possible and it resulted in mixtures of diastereomers, which could be tested as phase-transfer catalysts using the formation of a phenylalanine analog as a test reaction (up to 43% ee). A clear matched-mismatched situation was observed in the two diastereomeric series.

Dataset: 10.26037/yareta:fp326563trgt3gp3l3ofsyfiem

DOI : 10.1039/C9OB01355E 

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