Access to cyclopropanes with geminal trifluoromethyl and difluoromethylphosphonate groups

• Ita Hajdin,
• Romana Pajkert,
• Mira Keßler,
• Jianlin Han,
• Haibo Mei and
• Gerd-Volker Röschenthaler

Beilstein J. Org. Chem. 2023, 19, 541–549, doi:10.3762/bjoc.19.39

• stereochemistry of the main isomer, the 19F,1H-HOESY NMR spectrum of compound 6c was recorded. The spectrum shows direct correlation of one fluorine nucleus of the difluoromethyl phosphonate group with two cyclopropane protons at 1.75 and 2.91 ppm, respectively. Thus, it is conceivable that the major

• slight preference for one diastereoisomer. The presented results turn of a new page for the future of diazo chemistry. 19F,1H-HOESY spectrum of compound 6c. Previous works (A–D) and the extension (this work). Synthesis of diethyl 2-diazo-1,1,3,3,3-pentafluoropropylphosphonate (5). Scope of the

Efficient synthesis of dipeptide analogues of α-fluorinated β-aminophosphonates

• Marcin Kaźmierczak and
• Henryk Koroniak

Beilstein J. Org. Chem. 2020, 16, 756–762, doi:10.3762/bjoc.16.69

• worse results in each case. We assume it is associated with a much greater reactivity of this reagent in relation to PyFluor. The mechanism of the PyFluor-mediated deoxyfluorination of the α-hydroxy-β-aminophosphonates 5 was previously proposed. Based on spectroscopic studies (19F,1H-HOESY, 1H,1H-NOESY

Synthesis of 4-(2-fluorophenyl)-7-methoxycoumarin: experimental and computational evidence for intramolecular and intermolecular C–F···H–C bonds

• Vuyisa Mzozoyana,
• Fanie R. van Heerden and
• Craig Grimmer

Beilstein J. Org. Chem. 2020, 16, 190–199, doi:10.3762/bjoc.16.22

• conditions via a three-step reaction. The solution-state 1H NMR spectra of 6 showed a strong intramolecular interaction between F and H5 (JFH = 2.6 Hz) and 13C NMR suggested that this C–F···H–C coupling is a through-space interaction. The 2D 19F-{1H} HOESY and 1H-{19F} 1D experiments were done to confirm

• -doublets as observed in coumarin 5 and 6) and C5 as a singlet, indicating that they do not possess the through-space F···H5 or/and F···C5 coupling since the fluorine atom is a bit further away from H5 and C5. To confirm our findings, we further ran a 19F,1H-HOESY experiment and it showed clear H5···19F and

• -{19F} spectrum in CDCl3 and 1H spectrum and 1H-{19F} spectrum in acetone-d6. 13C NMR spectra for coumarin 5 and 6; showing the splitting of the signal corresponding to C5. 19F,1H-HOESY NMR spectrum for coumarin 6 illustrating two through-space interactions. Superposition of single-crystal X-ray

Hydrolysis, polarity, and conformational impact of C-terminal partially fluorinated ethyl esters in peptide models

• Vladimir Kubyshkin and
• Nediljko Budisa

Beilstein J. Org. Chem. 2017, 13, 2442–2457, doi:10.3762/bjoc.13.241

• . Characterization of model compounds 1H and 13C NMR spectra were assigned using 1H{19F} inverse-gated decoupled, 1H{13C} dept45, 1H{13C} HSQC, 1H-13C HMBC, 1H NOESY/EXSY and 19F{1H} HOESY experiments. For the minor s-cis conformation, only chemical shifts and, when possible, multiplicities are given. The

Synthesis of enones, pyrazolines and pyrrolines with gem-difluoroalkyl side chains

• Assaad Nasr El Dine,
• Ali Khalaf,
• Danielle Grée,
• Olivier Tasseau,
• Fares Fares,
• Nada Jaber,
• Philippe Lesot,
• Ali Hachem and
• René Grée

Beilstein J. Org. Chem. 2013, 9, 1943–1948, doi:10.3762/bjoc.9.230

• successfully developed for these sequential reactions. By carrying out various types of Pd-catalyzed coupling reactions for compounds with a p-bromophenyl substituent a route to focused chemical libraries was demonstrated. Keywords: 19F/1H HOESY; gem-difluoroalkyl derivatives; organo-fluorine compounds