Conjugate Addition of Nitroalkanes to an Acrylate Equivalent. Stereocontrol at C-α of the Nitro Group through Double Catalytic Activation

Silver-catalyzed regioselective hydroamination of alkenyl diazoacetates to synthesize γ-amino acid equivalents

A simple protocol to directly access γ-amino acid derivatives by intermolecular regioselective hydroamination of trichloroethyl alkenyldiazoacetates with carbamate using a silver tetrafluoroborate catalyst is described. Density functional theory (DFT) calculations to analyze the reaction mechanism revealed that multiple attractive interactions occur in a transition state to promote the vinylogous addition of nitrogen nucleophiles.

H8-BINOL chiral imidodiphosphoric acid catalyzed highly enantioselective aza-Friedel–Crafts reactions of pyrroles and enamides/imines

H₈-BINOL-type imidodiphosphoric acid (0.3–2 mol%) catalyzed highly enantioselective aza-Friedel–Crafts reactions of pyrroles and enamides/imines have been developed.

Camphor-derived C1-symmetric chiral diamine organocatalysts for asymmetric Michael addition of nitroalkanes to enones

A series of stable C(1)-symmetric chiral diamines (2a–2l) were conveniently synthesized by condensing exo-(-)-bornylamine or (+)-(1S,2S,5R)-menthylamine with various commercially available Cbz-protected amino acids. Among them, 2a can efficiently promote the Michael addition of nitroalkanes to a broad scope of enones with high yields (up to 96%) and excellent enantioselectivities (up to 98%) under mild conditions.

α-Hydroxy ketones as useful templates in asymmetric reactions

Approaching the Nature's efficiency in controlling both reactivity and stereoselectivity of organic reactions by means of a catalyst species remains a formidable challenge for chemists to face. Despite impressive advances in the design of novel catalysts and activation modes, current catalytic and asymmetric methodologies rarely meet desirable standards of robustness, substrate scope, and selectivity altogether. One trick to improve catalyst behaviour is to identify adequate substrate template-catalyst combinations so that optimum performance of the reaction system could be achieved. During the last couple of years α-hydroxy ketones, and most particularly α'-hydroxy enones, have emerged as useful templates with applications in a number of metal-catalyzed as well as organocatalyzed C-C and C-X bond-forming stereoselective reactions. The first review of these accomplishments is presented here along with a brief historical introduction.

Organocatalytic enantioselective Michael addition of malononitrile to nitroolefins catalyzed by bifunctional thiourea

A novel enantioselective Michael addition of malononitrile to trans-β-nitroolefins in the presence of bifunctional amine thiourea organocatalyst is developed. The Michael reaction catalyzed by amine thioureas containing both central and axial chiral elements proceeded smoothly and provided the desired adducts with high yields (up to 96% yield) and moderate enantioselectivities (up to 83% enantiomeric excess).