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Catalytic enantioselective [4+3] cycloaddition reaction between o-quinone methides and oxiranes was achieved by using a chiral N,N′-dioxide/TbIII complex as the catalyst, affording medium-sized hydrodioxepine derivatives in high yields (up to 99%) with good to excellent diastereo-(up to 94 : 6 dr) and enantioselectivities (up to 97% ee). The topographic steric maps and distribution of the buried volume (% VBur) of the catalysts via Cavallo's SambVca 2 tool were collected to effectively represent the chiral pocket of metal complexes of chiral N,N′-dioxides. [ABSTRACT FROM AUTHOR]

A highly enantioselective dearomative cascade reaction between 2-isocyanoethylindoles and 3-alkenyl-oxindoles was realized using a chiral N,N′-dioxide–Mg(ii) complex catalyst. This reaction provides a straightforward access to polycyclic 3-spirooxindoles bearing cyclopenta[b]indole units with four contiguous stereocenters in excellent yields and moderate to good stereoselectivities via a Michael/Friedel–Crafts/Mannich cascade. [ABSTRACT FROM AUTHOR]

A series of amide-based bifunctional organocatalysts have been utilized in asymmetric reactions. Prolinamide analogues have been designed to catalyze asymmetric reactions viaenamine intermediates with the assistance of tunable hydrogen bonding. In addition, the combination of various Lewis base functional groups, such as guanidine, N-oxide and phosphane, with an amide moiety have also constituted efficient bifunctional organocatalysts with unique reactivity and selectivity. [ABSTRACT FROM AUTHOR]

Chiral N,N′-dioxide–In(OTf)3 complexes were developed as efficient catalysts to catalyze the vinylogous Mukaiyama aldol reaction of the silyl dienol ester with aldehydes. The corresponding δ-hydroxy-α,β-unsaturated esters were obtained in up to 99% yield and 98% ee. Moreover, the obtained (R)-3v can be easily transformed to natural bioactive products. [ABSTRACT FROM AUTHOR]

The first catalytic asymmetric hetero-Diels–Alder reaction of Brassard's dienes with isatins was realized using Mg(ii)/N,N′-dioxide complexes as catalysts, affording the corresponding chiral spirolactones bearing tetrasubstituted centers in up to 99% yield with up to 99% ee and >99 : 1 dr within 3 hours. In the mechanism, based on the operando IR experiments, a predominant Diels–Alder pathway was found in the reaction. A possible transition state model was also proposed. [ABSTRACT FROM AUTHOR]