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Nickel-Catalyzed Asymmetric Three-Component Reaction of Unactivated Alkyl Halides, 1,3-Enynes and Aldehydes
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DOI：10.1002/anie.202520212.png)
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Abstract
En 中文
The π-propargylnickel(II) complexes, or their resonances, the η1-allenylnickel(II) ones, are typically generated from propargylic derivatives under Ni0 catalysis, and act as versatile electrophilic partners in diverse transformations. Here, we demonstrate that η1-propargylnickel(II) species can alternatively be generated from unactivated alkyl halides and 1,3-enynes via a Ni0-mediated radical alkylation of the alkene. Subsequent isomerization to η1-allenylnickel(II), followed by reduction, affords η1-allenylnickel(I) intermediates, which serve as reliable nucleophilic species for the stereoselective addition to aldehydes in the presence of benzoic acid. This protocol features broad substrate scope and good functional group tolerance, and nickel plays multiple roles in accomplishing a complicated Ni0/NiI/NiII/NiI/Ni0 catalytic cycle. A wide range of chiral homopropargylic alcohols, even the ones having a medium-sized ring, are modularly furnished in fair to good yields with moderate to excellent diastereo- and enantioselectivity. A series of control experiments and density functional theory (DFT) calculations are conducted to illuminate the catalytic pathways and the origin of regio- and stereoselectivity.
Keywords:
1,3-enyne
Aldehyde
Alkyl halide
Allenylnickel complex
Nickel
Reductive coupling
Journal
IF:
16.9
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5.6W
Citations:
53.0W