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We disclose a direct approach to the diastereoselective synthesis of phosphorus substituted N-acylaziridines based on a one-pot ZnCl2-catalyzed Joullié–Ugi three-component reaction of phosphorylated 2H-azirines, carboxylic acids and isocyanides. Hence, this robust protocol offers rapid access to an array of N-acylaziridines in moderate-to-good yields and up to 98:2 dr for substrates over a wide scope. The relevance of this synthetic methodology was achieved via a gram-scale reaction and the further derivatization of the nitrogen-containing three-membered heterocycle. The diastereo- and regioselective ring expansion of the obtained N-acylaziridines to oxazole derivatives was accomplished in the presence of BF3·OEt2 as an efficient Lewid acid catalyst. [ABSTRACT FROM AUTHOR]

A catalytic enantioselective entry to β2, 2-amino acids enabling their direct coupling with nucleophiles is described. The approach is based upon an effective bifunctional Brønsted base catalyzed construction of a quaternary carbon stereocenter at C4 position of pyrrolidin-2,3-diones. Subsequent regioselective Baeyer-Villiger oxidation of the resultant adducts gives β2, 2-amino acid N-carboxyanhydrides as the reactive species, which can further react with nucleophiles. Following this strategy both, β2, 2-amino acid derivatives with different functionalities at the newly created stereocenter, and spirocyclic structures can be efficiently prepared. [ABSTRACT FROM AUTHOR]

The desymmetrized meso-chimonantine core of leptosin C was prepared in a short stereoselective convergent sequence in 5 steps as the longest linear path from methyl L-tryptophan hydrochloride as starting material. The key step of this approach was a diastereoselective [4+2] cycloaddition between the bromooxindole and tryptophan derivatives allowing to define the adjacent quaternary benzylic centers in a high chemical yield. [ABSTRACT FROM AUTHOR]

Fully loaded: The ureidopeptide‐based bifunctional Brønsted base 1 efficiently promotes the first direct catalytic Michael reaction of α‐mercapto carboxylate surrogates with nitroolefins involving a fully substituted α‐carbon atom construction. [ABSTRACT FROM AUTHOR]