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A general and mild method for the synthesis of homoallylic 1,2-diamines from α-amino aldimines is reported. This method capitalizes on a low-loading iridium-catalyzed asymmetric umpolung allylation of imines and the following facile 2-aza-Cope rearrangement. The reagents are derived from readily available starting materials, and the catalytic system enables efficient construction of chiral vicinal diamines under mild conditions with broad functional group tolerance.
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http://dx.doi.org/10.1021/acs.orglett.5c02466 | DOI Listing |
Org Lett
August 2025
Henan Institute of Advanced Technology, Zhengzhou University, 100 Science Avenue, Zhengzhou 450001, China.
A nickel-catalyzed allylation of imines, including cyclic imines such as dibenzoxazepines, quinazolinones, and quinoxalin-2(1)-ones and linear imines, using allylic alcohols as pro-nucleophiles has been developed. This transformation affords homoallylic amines in good to excellent yields with high levels of regio- and diastereoselectivity. Mechanistic studies suggest that the bis(π-allyl)nickel(II) intermediate serves as a crucial intermediate in the catalytic cycle, exhibiting nucleophilic reactivity through its η,η coordination mode.
View Article and Find Full Text PDFOrg Lett
August 2025
Department of Chemistry, Indian Institute of Technology Ropar, Rupnagar, Punjab 140001, India.
We report a palladium-catalyzed sequential oxycyclization of indole-tethered allene to construct oxepino indole cores with yields up to 91%. This method showcases the C2 umpolung activation of indoles via η-π-allyl reactivity and enables efficient synthesis without side products. Furthermore, extensive mechanistic investigations, encompassing control experiments, X-ray crystallographic studies, and DFT analysis, have been conducted to elucidate the underlying mechanisms.
View Article and Find Full Text PDFOrg Lett
August 2025
Department of Nuclear Medicine, Laboratory of Clinical Nuclear Medicine, and Department of Radiology, Huaxi MR Research Center (HMRRC), Institution of Radiology and Medical Imaging, State Key Laboratory of Biotherapy and Cancer Center, West China Hospital, and School of Chemical Engineering, Sichuan
A general and mild method for the synthesis of homoallylic 1,2-diamines from α-amino aldimines is reported. This method capitalizes on a low-loading iridium-catalyzed asymmetric umpolung allylation of imines and the following facile 2-aza-Cope rearrangement. The reagents are derived from readily available starting materials, and the catalytic system enables efficient construction of chiral vicinal diamines under mild conditions with broad functional group tolerance.
View Article and Find Full Text PDFOrg Biomol Chem
April 2025
College of Biological, Chemical Sciences and Engineering, Jiaxing University, Jiaxing, 314001, P. R. of China.
Indole scaffolds, which are important structural motifs in organic chemistry, have garnered sustained interest due to their prevalence in pharmaceuticals, agrochemicals, and natural products. This study establishes a novel umpolung activation strategy for γ-position functionalization of electron-poor alkenyl sulfoxides, generating allylidenesulfonium intermediates that are subsequently trapped by indoles, achieving the synthesis of 3-functionalized indoles. Further transformations and plausible mechanism were investigated.
View Article and Find Full Text PDFJ Org Chem
December 2024
College of Chemical & Pharmaceutical Engineering, Hebei Province Key Laboratory of Molecular Chemistry for Drug, Hebei University of Science & Technology, Shijiazhuang 050018, China.
We report herein that three facile rearrangements of epoxy ketones can be employed for the efficient and practical synthesis of cephalotaxine, the parent member of the family of alkaloids. The Meinwald rearrangement of epoxy ketone (90%) was used for the preparation of the dense functional groups in the cyclopentane ring of cephalotaxine. A novel acid-catalyzed umpolung S2' rearrangement and the Wharton transposition reaction of epoxy ketones were also developed to synthesize the Mori intermediate via the key azaspiro allylic alcohols in a stereodivergent manner.
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