Chiral Brønsted Acid-Catalyzed Asymmetric Synthesis of N-Aryl-cis-aziridine Carboxylate Esters

We report a multi-component asymmetric Brønsted acid-catalyzed aza-Darzens reaction which is not limited to specific aromatic or heterocyclic aldehydes. Incorporating alkyl diazoacetates and, important for high ee's, ortho-tert-butoxyaniline our optimized reaction (i.e. solvent, temperature and catalyst study) affords excellent yields (61–98 %) and mostly >90 % optically active cis-aziridines. (+)-Chloramphenicol was generated in 4 steps from commercial starting materials. A tentative mechanism is outlined

Synthesis and asymmetric hydrogenation of (3E)-1-benzyl-3-[(2-oxopyridin-1(2H)-yl)methylidene]piperidine-2,6-dione

The synthesis of (3E)-1-benzyl-3-[(2-oxopyridin-1(2H)-yl)methylidene]piperidine-2,6-dione 4 from N-benzylglutarimide was achieved in three steps. The asymmetric hydrogenation of 4 gave either the product of partial reduction (10) or full reduction (13), depending on the catalyst which was employed, in high ee in each case. Attempts at asymmetric transfer hydrogenation (ATH) of 4 resulted in formation of a racemic product

New asymmetric synthesis of protein farnesyltransferase inhibitors via palladium-catalyzed cross-coupling reactions of 2-iodo-imidazoles.

International audiencePalladium catalyzed cross-coupling reactions of 2-iodoimidazole have been studied to synthesize imidazole-containing protein farnesyltransferase inhibitors. The Suzuki coupling reaction proved to be very efficient to introduce functionalized alkyl chains at the 2-position of the imidazole ring and a new synthesis of the required alkenylboronates was realised by a reaction of cross metathesis. Asymmetric synthesis of allyl succinic derivatives allowed us to synthesize chiral protein farnesyltransferase inhibitors through Suzuki coupling and to determine the influence of the stereochemistry of our inhibitors on the enzymatic activity