Ugi reaction-derived prolyl peptide catalysts grafted on the renewable polymer polyfurfuryl alcohol for applications in heterogeneous enamine catalysis

The multicomponent synthesis of prolyl pseudo-peptide catalysts using the Ugi reaction with furfurylamines or isocyanides is described. The incorporation of such a polymerizable furan handle enabled the subsequent polymerization of the peptide catalyst with furfuryl alcohol, thus rendering polyfurfuryl alcohol-supported catalysts for applications in heterogeneous enamine catalysis. The utilization of the polymer-supported catalysts in both batch and continuous-flow organocatalytic procedures proved moderate catalytic efficacy and enantioselectivity, but excellent diastereoselectivity in the asymmetric Michael addition of n-butanal to β-nitrostyrene that was used as a model reaction. This work supports the potential of multicomponent reactions towards the assembly of catalysts and their simultaneous functionalization for immobilization.

Solid Supported Peptide Catalyst for the Synthesis of Flavanone and Azaflavanones

A variety of flavanones and azaflavanones have been synthesised from chalcones, catalysed by 30 mol% solid support proline terminal peptide, which is mildly efficient with high conversions yields and could be recycled up to three times without significant loss in its activity.Keywords: , Solid Support Peptide Catalyst, Reusable Catalyst, Cyclisation, Flavanones

Organocatalyzed C–C Ring Construction: The Carreira Synthesis of (+)-Crotogoudin

Kazuaki Kudo of the University of Tokyo developed (Org. Lett. 2013, 15, 4964) a peptide catalyst for the enantioselective construction of 3 by the addition of 2 to 1. Thorsten Bach of the Technische Universität München devised (Science 2013, 342, 840; J. Am. Chem. Soc. 2013, 135, 14948) a Lewis acid organocatalyst for the photo­cyclization of 4 to 5. Albert Moyano of the Universitat de Barcelona effected (Eur. J. Org. Chem. 2013, 3103) enantioselective conjugate addition of 7 to 6 to give the cyclopentane 8. Daniel Romo of Texas A&M optimized (Nature Chem. 2013, 5, 1049) the addition of 9 to 10 to give the β-lactone 11. Kamal Kumar and Herbert Waldmann of the Technische Universität Dortmund found (Angew. Chem. Int. Ed. 2013, 52, 9576) that the addition of 12 to 13 followed by Bayer–Villiger oxidation and deacylation delivered 14 in high ee. David W. Lupton of Monash University opened (Angew. Chem. Int. Ed. 2013, 52, 9149) the cyclopropane of 15 in situ, leading to an ester enolate that added to 16 to give 17. Jeffrey S. Johnson of the University of North Carolina used (Chem. Sci. 2013, 4, 2828) an organocatalyst to mediate the addition of the prochiral 18 to 19, leading to 20. M. Belén Cid of the Universidad Autónoma de Madrid added (J. Org. Chem. 2013, 78, 10737) the nitroalkane 22 to the unsaturated aldehyde 21, leading, after intramolecular Julia-Kocienski addition, to the cyclohexene 23. Additions that pro­ceed in high ee with cyclopentenone and cyclohexenone are often not as selective with cycloheptenone 24. Wei Wang of the University of New Mexico and Wenhu Duan of the Shanghai Institute of Materia Medica observed (Tetrahedron Lett. 2013, 54, 3791) that addition of nitromethane and of nitroethane to 24 were both highly effective. Strategies have been developed for applying organocatalysis to the assembly of polycarbacyclic ring systems. Sanzhong Luo of the Beijing National Laboratory for Molecule Sciences uncovered (Synthesis 2013, 45, 1939) a simple amine that effi­ciently catalyzed the Robinson annulation of 26 with 27 to give 28.

Intracellular delivery of a catalytic organometallic complex

We show the intracellular delivery of a homogeneous palladium–peptide catalyst able to bioorthogonally activate a profluorophore inside living prostate cancer cells.

Function-oriented investigations of a peptide-based catalyst that mediates enantioselective allylic alcohol epoxidation.

Experimentally derived analysis of selectivity of a peptide catalyst through study of substrate scope, kinetics, catalyst analogues, and NMR data.