Herein we describe an efficient protocol for the regioselective addition of 1,3-dicarbonyl compounds to internal alkynes catalyzed by rhodium/Lewis acid catalysts. The corresponding branched/linear allylic alkylation products could be selectively obtained in good yields. Rh–H species were considered to be generated by direct C–H oxidative addition of 1,3-dicarbonyl compounds with rhodium catalyst with the assistance of Lewis acid. Moreover, a retro-allylic alkylation process was observed in this transformation.

A newly prepared chiral-at-metal Rh(III) complex catalyzed highly efficient asymmetric conjugate addition of para-vinylanilines with α,β-unsaturated 2-acyl imidazoles is developed, affording the corresponding adducts in 67–95% yields with 86–95% ee. Remarkably, employing as low as 0.05 mol % of Rh(III) complex as catalyst, a gram-scale reaction still affords the desired product in 81% yield with 92% ee.

Chiral-at-metal RhIII complexes catalyze the efficient enantioselective Mannich reaction of 2-acyl imidazoles with 1,3,5-triazinanes, affording the corresponding adducts in 81–99 % yield with up to >99 % enantioselectivity. This protocol performs with 0.1 mol-% of RhIII complex on gram scale without any loss in enantioselectivity.

We report an efficient enantioselective conjugate addition of photogenerated α-amino radicals to Michael acceptors catalyzed by a newly prepared chiral-at-metal rhodium complex. This protocol shows that a single Rh(III) complex can serve not only as a Lewis acid but also as a photoredox catalyst to control the stereoselectivity during the bond formation.

A catalytic enantioselective hydroxyamination of α,β-unsaturated 2-acyl imidazoles with N-protected hydroxyl amines catalyzed by a chiral-at-metal Rh(III) complex (0.5–2 mol%) has been developed. The approach affords valuable N-Boc protected β-amino acid derivatives in moderate to good yields with high enantioselectivity (up to 94% yield, 99.5% ee).

Chiral Rh(III) complex catalyzed highly efficient enantioselective cyclopropanation of α,β-unsaturated 2-acyl imidazoles or pyridine with 2-bromomalonate is developed to generate corresponding multisubstituted cyclopropanes in 70–99% yields with 93→99% enantioselectivity. The proficiency of the process is also demonstrated in gram scale reaction maintaining same reactivity and selectivity level in lower catalyst loading. Moreover, the developed methodology is applicable in challenging synthesis of biscyclopropane scaffold with 97% ee in a single operation.

A highly regio- and stereoselective Rh-catalyzed intermolecular head-to-head [2 + 2] cycloaddition of allenamides was developed. The intermolecular cycloadducts, trans-dimethylenecyclobutane-1,2-diamine derivatives, were achieved in good yields with high regioselectivity and stereoselectivity.

A direct and highly stereoselective approach for the synthesis of Z-alkenyl-pyranoindoles had been developed by utilizing Rh(II)-catalyzed intramolecular cyclization of N-sulfonyl-1,2,3-triazoles with indole derivatives. A variety of pyranoindoles were obtained in 44–93% yields. Moreover, a more convenient synthesis of pyranoindoles starting from terminal alkyne was realized via a Cu–Rh sequentially catalyzed one-pot cascade reaction.

An efficient approach for the synthesis of polycyclic spiroindolines has been developed by utilizing Rh(II)-catalyzed dearomatizing annulation of sulfonyl triazoles. An enantioselective variant of the process was also looked into briefly to achieve polycyclic spiroindolines in good yield with a promising 73.3: 26.7 enantiomeric ratio, demonstrating the potential for asymmetric catalysis.An efficient approach for the synthesis of polycyclic spiroindolines has been developed by utilizing Rh(II) catalyzed dearomatizing annulation of sulfonyl triazoles. The corresponding cyclization products were obtained in up to 93% yield.

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Palladium-catalyzed allylic esterifications of secondary homoallyl alcohols with acids via sequential retro-allylation and esterification are demonstrated, affording the corresponding allyl ester in up to 99% yield. The electron effect of the substituent of the secondary alcohol was found to be crucial to the selective C–C bond cleavage.

We aimed to describe an efficient CoCl2-catalyzed direct C–C bond formation of tetrahydrofuran (THF) with various alkynes in the presence of tert-butyl hydroperoxide and catalytic amount of acid to obtain vinyl-substituted THFs. Mono- and di-substituted alkynes were suitable for this transformation.We aimed to describe an efficient CoCl2-catalyzed direct C–C bond formation of tetrahydrofuran (THF) with various alkynes in the presence of tert-butyl hydroperoxide and catalytic amount of acid to obtain vinyl-substituted THFs. Mono- and di-substituted alkynes were suitable for this transformation.

A catalytic enantioselective hydroxyamination of α,β-unsaturated 2-acyl imidazoles with N-protected hydroxyl amines catalyzed by a chiral-at-metal Rh(III) complex (0.5–2 mol%) has been developed. The approach affords valuable N-Boc protected β-amino acid derivatives in moderate to good yields with high enantioselectivity (up to 94% yield, 99.5% ee).

A graphical abstract is available for this content

We report an efficient enantioselective conjugate addition of photogenerated α-amino radicals to Michael acceptors catalyzed by a newly prepared chiral-at-metal rhodium complex. This protocol shows that a single Rh(III) complex can serve not only as a Lewis acid but also as a photoredox catalyst to control the stereoselectivity during the bond formation.