Ni-catalyzed hydroalkylation of olefins with N-sulfonyl amines

Abstract

Hydroalkylation, the direct addition of a C(sp3)–H bond across an olefin, is a desirable strategy to produce valuable, complex structural motifs in functional materials, pharmaceuticals, and natural products. Herein, we report a reliable method for accessing α-branched amines via nickel-catalyzed hydroalkylation reactions. Specifically, by using bis(cyclooctadiene)nickel (Ni(cod)2) together with a phosphine ligand, we achieved a formal C(sp3)–H bond insertion reaction between olefins and N-sulfonyl amines without the need for an external hydride source. The amine not only provides the alkyl motif but also delivers hydride to the olefin by means of a nickel-engaged β–hydride elimination/reductive elimination process. This method provides a platform for constructing chiral α-branched amines by using a P-chiral ligand, demonstrating its potential utility in organic synthesis. Notably, a sulfonamidyl boronate complex formed in situ under basic conditions promotes ring-opening of the azanickellacycle reaction intermediate, leading to a significant improvement of the catalytic efficiency.

Ni-catalyzed arylation of alkynes with organoboronic acids and aldehydes to access stereodefined allylic alcohols

“…Acetophenone is a co-oxidant, while other alternatives like chlorobenzene and ketones are less reactive. 31 Herein, our preliminary results are shown in Scheme 3 ; diverse arylated allylic alcohols were generated in synthetically useful yields via the redox-triggered coupling of benzyl alcohols.…”

Iron-Catalyzed Oxidative α-Amination of Ketones with Primary and Secondary Sulfonamides

“…All reagents and solvents were purchased from various commercial sources and used without further purification, including 1,2-dichloroethane (anhydrous, SureSeal), chloroform D (99.8 atom % D, Millipore Sigma), deoxybenzoin (combiblocks), iron tribromide (anhydrous, Strem), iron trifluoride (anhydrous, Strem), iron(II) chloride (anhydrous, Strem), iron(II) trifluoromethanesulfonate (Strem), iron(II) acetate (anhydrous, Strem), iron(III) acetylacetonate (Strem), iron(III) trifluoromethanesulfonate (Alfa Aesar), benzyl 4-bromophenyl ketone (Acros Organics), benzyl 4-chlorophenyl ketone (TCI America), benzyl 4-fluorophenyl ketone (Matrix Scientific), tert -butyl magnesium chloride solution (1.0 M in THF, Millipore Sigma), benzylmagnesium chloride solution (2.0 M in THF, Millipore Sigma), thionyl chloride (1.0 M in DCM, Alfa Aesar), 4-methylbenzyl phenyl ketone (TCI America), silver hexafluorophosphate (TCI America), tetrahydrofuran (anhydrous, SureSeal, Millipore Sigma), 1,4-dioxane (anhydrous, SureSeal, Millipore Sigma), toluene (anhydrous, SureSeal, Millipore Sigma), sodium tert -butoxide (Thermo Scientific), p -toluenesulfonyl chloride (Thermo Scientific), isovalerophenone (TCI America), N -methyl- p -toluenesulfonamide (TCI America), and isobutyraldehyde (Thermo Scientific). 4-Methylphenyl benzyl ketone, 22 4-methoxyl benzyl ketone, 23 tert -butyl benzyl ketone, 24 biphenyl benzyl ketone, 25 4-fluorobenzyl phenyl ketone, 26 and N -( n -hexyl)- p -toluenesulfonamide 27 were synthesized via literature procedures. Iron-catalyzed reaction mixtures were assembled in a nitrogen-filled glovebox, and the vials were tightly sealed and removed from the glovebox for heating on an aluminum heating block with temperature control.…”

Ligand-Controlled Regiodivergent Nickel-Catalyzed Hydroaminoalkylation of Unactivated Alkenes

“…Our recent research focuses on developing C–C bond couplings between alkenes and imines through aza-nickelacycles, which are generated via oxidative cyclization of nickel(0) complexes with alkenes and imines . We have successfully achieved the nickel-catalyzed addition of styrenes to imines via aza-nickaleacycles, yielding allylic amines. , Building upon the aza-nickelacycle strategy, Shi group and ours independently reported nickel-catalyzed hydroaminoalkylation of styrenes with amines and imines, involving hydrogen transfer and reductive coupling, respectively. However, extending these reactions to unactivated alkenes has encountered significant challenges in achieving regioselectivity.…”