Diastereo-Divergent Synthesis of Saturated Azaheterocycles Enabled by tBuOK-Mediated Hydroamination of Alkenyl Hydrazones.

Diastereo-divergent synthesis of saturated azaheterocycles has been achieved by tBuOK-mediated hydroamination of alkenyl hydrazones. DFT calculations suggested that the cation-π interactions between a potassium cation and aryl substituents on hydrazones give rise to 2,5-cis selectivity in pyrrolidines, which were synthesized by the reaction of γ,δ-unsaturated N-benzyl hydrazones. By contrast, 2,5-trans selectivity was observed when an isopropyl group was used as the substituent on hydrazones.

Inorganic-base-mediated hydroamination of alkenyl oximes for the synthesis of cyclic nitrones.

A method based on hydroamination mediated by inorganic base was developed for the synthesis of cyclic nitrones from alkenyl oximes. DFT calculations of the reaction pathway suggested that this hydroamination could proceed through an unprecedented nucleophilic amination of the unactivated alkene by the oxime nitrogen atom. The transition state of this reaction is stabilized by an ionic interaction between a metal cation such as K(+) and the oxime oxygen and negatively charged alkene moiety.

Pd(0)-catalyzed sequential C-N bond formation via allylic and aromatic C-H amination of α-methylstyrenes with diaziridinone.

A novel Pd(0)-catalyzed sequential C-N bond formation process via allylic and aromatic C-H amination of α-methylstyrenes with di-tert-butyldiaziridinone, giving spirocyclic indolines in good yields, is described. Four C-N bonds and one spiro quaternary carbon are generated in a single operation.

Cu(I)-catalyzed diamination of conjugated dienes. Complementary regioselectivity from two distinct mechanistic pathways involving Cu(II) and Cu(III) species.

Conjugated dienes can be diaminated at the internal and/or terminal double bonds using Cu(I) as catalyst and N,N-di-t-butyldiaziridinone (1) as nitrogen source. The regioselectivity is highly dependent upon the choice of Cu(I) catalyst and the substituents on diene substrates. The diamination likely proceeds via two mechanistically distinct pathways.

New reactivity of oxaziridine: Pd(II)-catalyzed aromatic C-H ethoxycarbonylation via C-C bond cleavage.

A novel Pd(II)-catalyzed aromatic C-H ethoxycarbonylation with oxaziridine involving C-C bond cleavage is described. Various aromatic 2-phenylpyridines and related compounds as well as aryl ureas can be effectively ethoxycarbonylated. A catalytic cycle involving Pd(II) and Pd(IV) is proposed.

Cu(I)-catalyzed regioselective diamination of conjugated dienes via dual mechanistic pathways.

This paper describes the Cu(I)-catalyzed regioselective diamination of conjugated dienes using di-tert-butyldiaziridinone as nitrogen source. The internal diamination and terminal diamination likely proceed via two mechanistic pathways. Various dienes can be efficiently diaminated at the internal double bonds with high regio- and diasteroselectivity in good yield using inexpensive CuBr as catalyst.

Magnetically separable Pd catalyst for carbonylative Sonogashira coupling reactions for the synthesis of alpha,beta-alkynyl ketones.

A magnetically separable palladium catalyst was simply synthesized through a wet impregnation incorporating palladium nanoparticles and superparamagnetic Fe3O4 nanoparticles in KBH4 solution, which is a highly efficient catalyst for the carbonylative Sonogashira coupling reaction of aryl iodides with terminal alkynes under phosphine-free conditions. This catalyst is completely magnetically recoverable due to the super paramagnetic behavior of Fe3O4 and can be reused with sustained selectivity and activity.

Modular chiral bidentate phosphonites: design, synthesis, and application in catalytic asymmetric hydroformylation reactions.

A new class of C2-symmetric chiral bidentate phosphonite ligands has been synthesized in moderate to good yields from readily available starting materials. Application of these air-stable chiral phosphonites in the Rh I-catalyzed asymmetric hydroformylation of styrene derivatives, vinyl acetate, and allyl cyanide afforded the corresponding chiral aldehydes with high regio- and enantioselectivities under mild reaction conditions. The modular nature of the ligands allows fine-tuning of the selectivities through judicious modifications of the substituents on the ligand backbone.