Access to optically active tetrafluoroethylenated amines based on [1,3]-proton shift reaction

• Yuta Kabumoto,
• Eiichiro Yoshimoto,
• Bing Xiaohuan,
• Masato Morita,
• Motohiro Yasui,
• Shigeyuki Yamada and
• Tsutomu Konno

Beilstein J. Org. Chem. 2024, 20, 2776–2783, doi:10.3762/bjoc.20.233

• a smooth [1,3]-proton shift reaction with a high chirality transfer, affording the corresponding rearranged products in acceptable yields. Without purification, these products were subjected to acid hydrolysis and the subsequent N-Cbz protection, providing the optically active tetrafluoroethylenated

• amides in moderate three-step yields. Keywords: amine; chirality transfer; [1,3]-proton shift reaction; tetrafluoroethylene fragment; Introduction A fluorine atom has quite peculiar chemical and physical properties compared to others, and hence changes in molecular properties resulting from the

• a tetrafluoroethylene group on an asymmetric carbon center. In order to overcome the current lack of synthetic methods for preparing such molecules, we came up with the idea of utilizing the [1,3]-proton shift reaction reported by Soloshonok et al. In 1997, Soloshonok et al. reported that

Characterization of two new degradation products of atorvastatin calcium formed upon treatment with strong acids

• Jürgen Krauß,
• Monika Klimt,
• Markus Luber,
• Peter Mayer and
• Franz Bracher

Beilstein J. Org. Chem. 2019, 15, 2085–2091, doi:10.3762/bjoc.15.206

• ][22]. For benzanilides Tu [21] proposed a mechanism involving protonation of the amide oxygen, followed by 1,3 proton shift to the ring carbon next to the amide carbonyl group, followed by elimination of protonated phenyl isocyanate under re-aromatization. For the pyrrole derived substrate

Base-promoted isomerization of CF₃-containing allylic alcohols to the corresponding saturated ketones under metal-free conditions

• Yoko Hamada,
• Tomoko Kawasaki-Takasuka and
• Takashi Yamazaki

Beilstein J. Org. Chem. 2017, 13, 1507–1512, doi:10.3762/bjoc.13.149

• reported intriguing 1,3-proton shift of 4,4,4-trifluorobut-2-yn-1-ols was successfully extended to the 4,4,4-trifluorobut-2-en-1-ol system under metal-free conditions to afford the corresponding saturated ketones in high to excellent chemical yields using such a convenient and easy-to-handle base as DBU at

• the toluene refluxing temperature, and utilization of the corresponding optically active substrates unambiguously demonstrated that this transformation proceeded in a highly stereoselective fashion. Keywords: allylic alcohols; chirality; computation; 1,3-proton shift; trifluoromethyl; Introduction

Oxidative 3,3,3-trifluoropropylation of arylaldehydes

• Akari Ikeda,
• Masaaki Omote,
• Shiho Nomura,
• Miyuu Tanaka,
• Atsushi Tarui,
• Kazuyuki Sato and
• Akira Ando

Beilstein J. Org. Chem. 2013, 9, 2417–2421, doi:10.3762/bjoc.9.279

• )silane (1) and arylaldehydes 2 was triggered by fluoride anions to afford aryl 3,3,3-trifluoropropyl ketones 3 in moderate to good yield. A mechanistic study of this reaction indicated that it occurred via an allyl alkoxide (4). A subsequent 1,3-proton shift of the benzylic proton of 4 forms 3. This

• reaction involves oxidative 3,3,3-trifluoropropylation of an arylaldehyde to afford 4,4,4-trifluoro-1-arylbutan-1-one. Keywords: cesium fluoride; organo-fluorine; 1,3-proton shift; trifluoromethyl; 3,3,3-trifluoropropenyl; Introduction Trifluoromethyl groups are an essential motif in pharmaceuticals

• product in which deuterium was inserted on the α- and β-carbons of the carbonyl group with rates of 22% and 53%, respectively (Scheme 1, (1)). This result suggests that deuterium on the β-carbon should be incorporated by a 1,3-proton shift. In contrast, deuterium on the α-carbon should be inserted when

Intramolecular hydroamination of alkynic sulfonamides catalyzed by a gold–triethynylphosphine complex: Construction of azepine frameworks by 7-exo-dig cyclization

• Hideto Ito,
• Tomoya Harada,
• Hirohisa Ohmiya and
• Masaya Sawamura

Beilstein J. Org. Chem. 2011, 7, 951–959, doi:10.3762/bjoc.7.106

• cationic gold center coordinates with 4a to form the gold–alkyne complex A. Intramolecular nucleophilic attack of the nitrogen atom affords the 7-exo-dig cyclization product B with an exocyclic C–C double bond. The protonated N-sulfonylenamide B tautomerizes to iminium ion C through 1,3-proton shift, or