Zn(II)-Catalyzed Isomerization/Asymmetric [3+2] Cycloaddition of 3-Butynoyl Pyrazole with Nitrones: Subsequent Exocyclic Olefin Isomerization and Capture
A highly efficient Zn(OTf)<sub>2</sub>-catalyzed tandem isomerization/[3+2] cycloaddition cascade of 3-butynoyl pyrazole with nitrones was reported using a C<sub>1</sub>-symmetric imidazolidine-pyrroloimidazolone pyridine ligand. The resulting cycloadducts readily isomerize with silica gel or Et<sub>3</sub>N to chiral 4-isoxazolines containing an endocyclic C═C bond in up to 93% yield with 99% ee. The exocyclic olefin intermediate is effectively trapped by 1,4-benzoquinone ester under Cu(II) catalysis to afford chiral spiroketal analogues with >20:1 dr.
Authors
- Jiayi Liu (ORCID: https://orcid.org/0009-0002-4448-7781)
- Ming‐Sheng Xie (ORCID: https://orcid.org/0000-0003-4113-2168)
- Hai‐Ming Guo (ORCID: https://orcid.org/0000-0003-0629-4524)
- Xinyi Chen (ORCID: https://orcid.org/0000-0001-5084-7849)
Institutions
- Henan Normal University (CN)
Publication Details
- Journal
- Organic Letters
- Published
- 2025-12-08
- DOI
- https://doi.org/10.1021/acs.orglett.5c04591
- Primary Topic
- Catalytic Alkyne Reactions
- Type
- article
- Field-Weighted Citation Impact
- 0.00