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DOI: 10.1055/s-0033-1340402
Organocatalytic Total Syntheses of (+)- and (–)-Trigonoliimine A
Publikationsverlauf
Publikationsdatum:
13. Dezember 2013 (online)
![](https://www.thieme-connect.de/media/synfacts/201401/i_b114_s1_10-1055_s-0033-1340402.gif)
Significance
The Zhu group reports an enantioselective Michael addition of methyl α-aryl-α-isocyanoacetates to vinyl phenylselenone catalyzed by a cinchona-alkaloid derivative. The obtained enantioenriched α-aryl-α-(2′-phenylselenonylethyl)-α-isocyanoacetates are successfully transformed into linear and cyclic quaternary α-amino acids, oxindoles, and pyrrolidinones. A concise total synthesis of (+) and (–)-trigonoliimine A (9 steps, 7.5% and 6.8% overall yield) from the shown Michael adduct was completed via a modified Bischler–Napieralski cyclization.
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Comment
α-Isocyanoacetates are well-established glycine templates for the synthesis of racemic α,α-disubstituted α-amino acids. Yet, the catalytic enantioselective allylation of α-isocyanoacetates remains underexploited. The reported Michael addition products are converted further without racemization into the corresponding amines and azides. The absolute configuration of the products obtained from the shown cinchona-alkaloid catalyst was determined after derivatization by X-ray analysis to be R.
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![](https://www.thieme-connect.de/media/synfacts/201401/i_b114_s1_10-1055_s-0033-1340402.gif)