A highly efficient asymmetric cascade reaction between keto esters and alkynyl alcohols and amides is reported. The success of the reaction was attributed to the combination of chiral Lewis acid N,N′-dioxide nickel(II) catalysis with achiral π-acid gold(I) catalysis working as an asymmetric relay catalytic system. The corresponding spiroketals and spiroaminals were synthesized in up to 99 % yield, 19:1 d.r., and more than 99 % ee under mild reaction conditions. Control experiments suggest that the N,N′-dioxide ligand was essential for the formation of the spiro products.

The highly enantioselective alkynylation of isatins, catalyzed by a bifunctional guanidine/CuI catalyst under mild reaction conditions, is described. The reaction is broad in scope with respect to alkyl/aryl-substituted terminal alkynes and substituted isatins, thus affording bioactive propargylic alcohols in excellent yields and enantioselectivities.

Highly efficient kinetic resolution of 2H-azirines by an asymmetric imine amidation was achieved in the presence of a chiral N,N′-dioxide/Sc^III complex, thus providing a promising method to obtain the enantioenriched 2H-azirine derivatives and protecting-group free aziridines at the same time. It is rare to find an example of N1 of an oxindole participating in a reaction over C3. Moreover, chiral 2H-azirines were stereospecifically transformed into an unprotected aziridine and α-amino ketone.

Highly efficient kinetic resolution of 2H-azirines by an asymmetric imine amidation was achieved in the presence of a chiral N,N′-dioxide/Sc^III complex, thus providing a promising method to obtain the enantioenriched 2H-azirine derivatives and protecting-group free aziridines at the same time. It is rare to find an example of N1 of an oxindole participating in a reaction over C3. Moreover, chiral 2H-azirines were stereospecifically transformed into an unprotected aziridine and α-amino ketone.

The asymmetric propargyl Claisen rearrangement provides a convenient entry to chiral allene motifs. Herein, we describe the development of a kinetic resolution and asymmetric rearrangement of racemic propargyl vinyl ethers. This transformation afforded chiral allene products along with the enantiomerically enriched substrate in good yields with excellent diastereo- and enantioselectivity. The complete chirality transfer and facially selective rearrangement enabled the simultaneous construction of an axially chiral allenic unit and a quaternary carbon stereocenter.

A highly efficient asymmetric cascade reaction between keto esters and alkynyl alcohols and amides is reported. The success of the reaction was attributed to the combination of chiral Lewis acid N,N′-dioxide nickel(II) catalysis with achiral π-acid gold(I) catalysis working as an asymmetric relay catalytic system. The corresponding spiroketals and spiroaminals were synthesized in up to 99 % yield, 19:1 d.r., and more than 99 % ee under mild reaction conditions. Control experiments suggest that the N,N′-dioxide ligand was essential for the formation of the spiro products.

A highly efficient enantioselective [2+2] cycloaddition between alkynones and cyclic enol silyl ethers was developed by using a chiral N,N′-dioxide-zinc(II) complex as a catalyst. This method functions well for a variety of terminal alkynes as well as cyclic enol silyl ethers, with good to excellent enantioselectivity (up to 97 % ee). This is also the first successful example for the catalytic enantioselective [2+2] cycloaddition of internal alkynes with cyclic enol silyl ethers to give fully substituted cyclobutenes. Meanwhile, the desired cyclobutene product can easily be transformed into fused cyclobutane derivatives.

The highly enantioselective alkynylation of isatins, catalyzed by a bifunctional guanidine/CuI catalyst under mild reaction conditions, is described. The reaction is broad in scope with respect to alkyl/aryl-substituted terminal alkynes and substituted isatins, thus affording bioactive propargylic alcohols in excellent yields and enantioselectivities.

An N,N′-dioxide/scandium(III) complex catalyzed, highly efficient conjugate addition of malonic esters to enynes is described. A range of trisubstituted 1,2-allenyl ketones were obtained in high yields (up to 99 %) with good d.r. (up to 95/5) and excellent ee values (97 %–99 %). Moreover, the products could be easily transformed into chiral furan and 5-hydroxypyrazoline derivatives, both of which are important skeletons of many biologically active compounds and pharmacologicals.

An N,N′-dioxide/scandium(III) complex catalyzed, highly efficient conjugate addition of malonic esters to enynes is described. A range of trisubstituted 1,2-allenyl ketones were obtained in high yields (up to 99 %) with good d.r. (up to 95/5) and excellent ee values (97 %–99 %). Moreover, the products could be easily transformed into chiral furan and 5-hydroxypyrazoline derivatives, both of which are important skeletons of many biologically active compounds and pharmacologicals.

A highly efficient enantioselective [2+2] cycloaddition between alkynones and cyclic enol silyl ethers was developed by using a chiral N,N′-dioxide-zinc(II) complex as a catalyst. This method functions well for a variety of terminal alkynes as well as cyclic enol silyl ethers, with good to excellent enantioselectivity (up to 97 % ee). This is also the first successful example for the catalytic enantioselective [2+2] cycloaddition of internal alkynes with cyclic enol silyl ethers to give fully substituted cyclobutenes. Meanwhile, the desired cyclobutene product can easily be transformed into fused cyclobutane derivatives.

The asymmetric propargyl Claisen rearrangement provides a convenient entry to chiral allene motifs. Herein, we describe the development of a kinetic resolution and asymmetric rearrangement of racemic propargyl vinyl ethers. This transformation afforded chiral allene products along with the enantiomerically enriched substrate in good yields with excellent diastereo- and enantioselectivity. The complete chirality transfer and facially selective rearrangement enabled the simultaneous construction of an axially chiral allenic unit and a quaternary carbon stereocenter.

The asymmetric CH insertion of α-diazoesters into 1-alkynes was achieved using chiral cationic guanidinium salts and copper(I) complexes. Optically active 2,4-disubstituted allenoates were generated under mild reaction conditions from various α-diazoesters and 1-alkynes in high yield (up to 99 %) and enantioselectivity (up to 97:3 e.r.). Control experiments excluded the possibility of an asymmetric isomerization of alkynoates.

An asymmetric aza-Diels–Alder reaction of 3-vinylindoles with isatin-derived ketimines has been developed. A series of spiroindolone derivatives were thus obtained in good to excellent yields with excellent enantioselectivity (up to 96 % yield and 99 % ee). Furthermore, the antimalarial compound NITD609 could be obtained in three steps with an overall yield of 40.6 %. Control experiments and operando IR experiments imply a concerted reaction pathway. The regioselectivity and exo selectivity result from π–π interactions between the two indoline rings of the two reactants.

A highly efficient asymmetric dearomatization of indoles was realized through a cascade reaction between 2-isocyanoethylindole and alkylidene malonates catalyzed by a chiral N,N′-dioxide/Mg^II catalyst. Fused polycyclic indolines containing three stereocenters were afforded in good yields with excellent diastereo- and enantioselectivities through a Michael/Friedel–Crafts/Mannich cascade. When 2-substituted 2-isocyanoethylindoles were used, spiroindoline derivatives were obtained through a Michael/Friedel–Crafts reaction.

A highly efficient asymmetric ring-opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N′-dioxide–scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99 % yield and 95 % ee. This is also the first example of one catalytic system working for the ring-opening reaction of donor–acceptor cyclopropanes with three different nucleophiles, let alone in an asymmetric version.

The asymmetric CH insertion of α-diazoesters into 1-alkynes was achieved using chiral cationic guanidinium salts and copper(I) complexes. Optically active 2,4-disubstituted allenoates were generated under mild reaction conditions from various α-diazoesters and 1-alkynes in high yield (up to 99 %) and enantioselectivity (up to 97:3 e.r.). Control experiments excluded the possibility of an asymmetric isomerization of alkynoates.

The asymmetric ring-opening/cyclization of cyclopropyl ketones with primary amine nucleophiles was catalyzed by a chiral N,N′-dioxide/scandium(III) complex through a kinetic resolution process. A broad range of cyclopropyl ketones and primary amines are suitable substrates of this reaction. The corresponding products were afforded in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield) under mild reaction conditions. This method provides a promising access to chiral 2,3-dihydropyrroles as well as an effective procedure for the kinetic resolution of 2-substituted cyclopropyl ketones.

A highly efficient asymmetric ring-opening reaction of cyclopropyl ketones with a broad range of thiols, alcohols and carboxylic acids has been first realized by using a chiral N,N′-dioxide–scandium(III) complex as catalyst. The corresponding sulfides, ethers, and esters were obtained in up to 99 % yield and 95 % ee. This is also the first example of one catalytic system working for the ring-opening reaction of donor–acceptor cyclopropanes with three different nucleophiles, let alone in an asymmetric version.

An asymmetric aza-Diels–Alder reaction of 3-vinylindoles with isatin-derived ketimines has been developed. A series of spiroindolone derivatives were thus obtained in good to excellent yields with excellent enantioselectivity (up to 96 % yield and 99 % ee). Furthermore, the antimalarial compound NITD609 could be obtained in three steps with an overall yield of 40.6 %. Control experiments and operando IR experiments imply a concerted reaction pathway. The regioselectivity and exo selectivity result from π–π interactions between the two indoline rings of the two reactants.

A highly efficient asymmetric dearomatization of indoles was realized through a cascade reaction between 2-isocyanoethylindole and alkylidene malonates catalyzed by a chiral N,N′-dioxide/Mg^II catalyst. Fused polycyclic indolines containing three stereocenters were afforded in good yields with excellent diastereo- and enantioselectivities through a Michael/Friedel–Crafts/Mannich cascade. When 2-substituted 2-isocyanoethylindoles were used, spiroindoline derivatives were obtained through a Michael/Friedel–Crafts reaction.

The asymmetric ring-opening/cyclization of cyclopropyl ketones with primary amine nucleophiles was catalyzed by a chiral N,N′-dioxide/scandium(III) complex through a kinetic resolution process. A broad range of cyclopropyl ketones and primary amines are suitable substrates of this reaction. The corresponding products were afforded in excellent enantioselectivities and yields (up to 97 % ee and 98 % yield) under mild reaction conditions. This method provides a promising access to chiral 2,3-dihydropyrroles as well as an effective procedure for the kinetic resolution of 2-substituted cyclopropyl ketones.

Efficient enantioselective NH insertion reactions of secondary and primary anilines were catalyzed by palladium(0) in combination with chiral guanidine derivatives. A broad range of substituted anilines were tolerated, and the corresponding products were obtained in high yield (up to 99 %) with good enantioselectivity (up to 94 % ee) under mild reaction conditions. The NH insertion mechanism was examined by the study of kinetic isotope effects, control experiments, HRMS, and spectroscopic analysis.

Efficient enantioselective NH insertion reactions of secondary and primary anilines were catalyzed by palladium(0) in combination with chiral guanidine derivatives. A broad range of substituted anilines were tolerated, and the corresponding products were obtained in high yield (up to 99 %) with good enantioselectivity (up to 94 % ee) under mild reaction conditions. The NH insertion mechanism was examined by the study of kinetic isotope effects, control experiments, HRMS, and spectroscopic analysis.

The asymmetric Kinugasa reaction was performed on pure water for the first time without the need for any organic co-solvents. In contrast to most asymmetric Kinugasa reactions, trans-β-lactams were obtained as the major products in good yields, enantioselectivities, and diastereoselectivities (up to 90 % yield, 98 % ee, and >99:1 d.r.). This reaction is atom-economical, environmentally friendly, and affords synthetically useful but challenging products.

Chiral N,N′-dioxide/Zn(NTf₂)₂ complexes were demonstrated to be highly effective in the direct asymmetric conjugate addition of arylacetonitriles to alkylidene malonates under mild conditions. A wide range of substrates were tolerated to afford their corresponding products in moderate-to-good yields with high diastereoselectivities (82:18–>99:1 d.r.) and enantioselectivities (81–99 % ee). The reactions performed well, owing to the high Lewis acidity of the metal triflimidate and a ligand-acceleration effect. The N,N′-dioxide also benefited the deprotonation process as a Brønsted base. The catalytic reaction could be performed on the gram-scale with retention of yield, diastereoselectivity, and enantioselectivity. The products that contained functional groups were ready for further manipulation. In addition, a possible catalytic model was proposed to explain the origin of the asymmetric induction.

Chiral 2-substituted-1,5-benzodiazepine derivatives were synthesized for the first time from an enantioselective domino reaction involving o-phenylenediamine and 2′-hydroxychalcones. The titanium complex formed from chiral ligand 1a derived from (S)-BINOL and L-prolineamide promoted the reaction and gave the products in good yields with up to 82 % ee.

The N,N′-dioxide–Sc(OTf)₃ complex was applied in the asymmetric Michael reaction of 1H-benzotriazole with chalcones to give the corresponding N-1 products in excellent yields (up to 99 %) with excellent enantioselectivities (up to 99 % ee). Further transformation into other optically active derivatives such as β-benzotriazolyl ester, alcohol, and amide were also realized with excellent results.

A highly enantioselective Friedel–Crafts alkylation of indoles with ethyl trifluoropyruvate has been developed using N,N′-dioxide-zinc(II) complexes. Both enantiomers of the desired adducts were obtained by the use of enantiomeric ligands in excellent results (up to 99% yield and 98% ee) within 0.5 h under mild conditions. On the basis of the experimental results, a proposed working model was proposed to explain the origin of the asymmetric induction.