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Abstract Because internal alkenes are more challenging synthetic targets than terminal alkenes, metal‐catalyzed olefin mono‐transposition (i.e., positional isomerization) approaches have emerged to afford valuableE‐ orZ‐internal alkenes from their complementary terminal alkene feedstocks. However, the applicability of these methods has been hampered by lack of generality, commercial availability of precatalysts, and scalability. Here, we report a nickel‐catalyzed platform for the stereodivergentE/Z‐selective synthesis of internal alkenes at room temperature. Commercial reagents enable this one‐carbon transposition of terminal alkenes to valuableE‐ orZ‐internal alkenes via a Ni−H‐mediated insertion/elimination mechanism. Though the mechanistic regime is the same in both systems, the underlying pathways that lead to each of the active catalysts are distinct, with theZ‐selective catalyst forming from comproportionation of an oxidative addition complex followed by oxidative addition with substrate and theE‐selective catalyst forming from protonation of the metal by the trialkylphosphonium salt additive. In each case, ligand sterics and denticity control stereochemistry and prevent over‐isomerization.
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Copper‐Catalyzed Asymmetric Acylboration of 1,3‐Butadienylboronate with Acyl Fluorides
Abstract We report herein a Cu‐catalyzed regio‐, diastereo‐ and enantioselective acylboration of 1,3‐butadienylboronate with acyl fluorides. Under the developed conditions, the reactions provide (Z)‐β,γ‐unsaturated ketones bearing an α‐tertiary stereocenter with highZ‐selectivity and excellent enantioselectivities. While direct access to highly enantioenrichedE‐isomers was not successful, we showed that such molecules can be synthesized with excellentE‐selectivity and optical purities via Pd‐catalyzed alkene isomerization from the correspondingZ‐isomers. The orthogonal chemical reactivities of the functional groups embedded in the ketone products allow for diverse chemoselective transformations, which provides a valuable platform for further derivatization.
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- Award ID(s):
- 2426500
- PAR ID:
- 10537157
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Angewandte Chemie International Edition
- Volume:
- 62
- Issue:
- 43
- ISSN:
- 1433-7851
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript
- Journal Article:
- https://doi.org/10.1002/anie.202304796
