fluorine

Janus Face All‐cis 1,2,4,5‐tetrakis(trifluoromethyl)‐ and All‐cis 1,2,3,4,5,6‐hexakis(trifluoromethyl)‐ Cyclohexanes

Janus Face All‐cis 1,2,4,5‐tetrakis(trifluoromethyl)‐ and All‐cis 1,2,3,4,5,6‐hexakis(trifluoromethyl)‐ Cyclohexanes

All‐cis 1,2,4,5‐tetrakis (trifluoromethyl)‐ and all‐cis 1,2,3,4,5,6‐hexakis (trifluoromethyl)‐ cyclohexanes were prepared by direct aryl hydrogenation. All‐cis 1,2,3,4,5,6‐hexakis(trifluoromethyl)cyclohexane has a high barrier to ring inversion (ΔG=27 kcal mol−1) and a Janus face profile with a large diffuse negative density on the fluorine face, and a focused positive density on the hydrogen face which coordinates carbonyls and halides.

Abstract

We report the synthesis of all‐cis 1,2,4,5‐tetrakis (trifluoromethyl)‐ and all‐cis 1,2,3,4,5,6‐hexakis (trifluoromethyl)‐ cyclohexanes by direct hydrogenation of precursor tetrakis‐ or hexakis‐ (trifluoromethyl)benzenes. The resultant cyclohexanes have a stereochemistry such that all the CF3 groups are on the same face of the cyclohexyl ring. All‐cis 1,2,3,4,5,6‐hexakis(trifluoromethyl)cyclohexane is the most sterically demanding of the all‐cis hexakis substituted cyclohexanes prepared to date, with a barrier (ΔG) to ring inversion calculated at 27 kcal mol−1. The X‐ray structure of all‐cis 1,2,3,4,5,6‐hexakis(trifluoromethyl)cyclohexane displays a flattened chair conformation and the electrostatic profile of this compound reveals a large diffuse negative density on the fluorine face and a focused positive density on the hydrogen face. The electropositive hydrogen face can co‐ordinate chloride (K≈103) and to a lesser extent fluoride and iodide ions. Dehydrofluorination promoted decomposition occurs with fluoride ion acting as a base.

Wiley: Angewandte Chemie International Edition: Table of Contents
Authors: Cihang Yu, Agnes Kütt, Gerd‐Volker Röschenthaler, Tomas Lebl, David B. Cordes, Alexandra M. Z. Slawin, Michael Bühl, David O’Hagan
doi.org/10.1002/anie.202008662

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Synthesis of Diverse Aromatic Ketones through C−F Cleavage of Trifluoromethyl Group

Synthesis of Diverse Aromatic Ketones through C−F Cleavage of Trifluoromethyl Group

Make the cut: An efficient synthetic method of aromatic ketones through C−F cleavage of trifluoromethyl group is disclosed. The high functional group tolerance of the transformation and the remarkable stability of trifluoromethyl group in various reactions enabled multi‐substituted aromatic ketone synthesis in an efficient route involving useful transformations such as ortho‐lithiation, aryne chemistry, and cross‐couplings.

Abstract

An efficient synthetic method of aromatic ketones through C−F cleavage of trifluoromethyl group is disclosed. The high functional group tolerance of the transformation and the remarkable stability of trifluoromethyl group in various reactions enabled multi‐substituted aromatic ketone synthesis in an efficient route involving useful transformations such as ortho‐lithiation, aryne chemistry, and cross‐couplings.

Wiley: Chemistry – A European Journal: Table of Contents
Authors: Mai Ikeda, Tsubasa Matsuzawa, Takamoto Morita, Takamitsu Hosoya, Suguru Yoshida
chemistry-europe.onlinelibrary.wiley.com/doi/abs/10.1002/chem.202001816

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Difluoroacetaldehyde N‐Triftosylhydrazone (DFHZ‐Tfs) as a Bench‐Stable Crystalline Diazo Surrogate for Diazoacetaldehyde and Difluorodiazoethane


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  • 18F-Trifluoromethanesulfinate Enables Direct C–H 18F-Trifluoromethylation of Native Aromatic Residues in Peptides

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  • Open-Shell Fluorination of Alkyl Bromides: Unexpected Selectivity in a Silyl Radical-Mediated Chain Process

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  • Studies of Halogen Bonding Induced by Pentafluorosulfanyl Aryl Iodides: A Potential Group of Halogen Bond Donors in a Rational Drug Design

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  • Rapid Entry into Biologically Relevant a,a-Difluoroalkylphosphonates Bearing Allyl Protection–Deblocking under Ru(II)/(IV)-Catalysis

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  • Site‐Selective, Modular Diversification of Polyhalogenated Aryl Fluorosulfates (ArOSO2F) Enabled by an Air‐Stable Pd(I) Dimer

    Very interesting solvent effect described by Schoenebeck, making it possible to selectively couple @ C-Br, then @ C-OSO2F, and finally @ C-Cl bonds on a range of substrates.
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  • M. Mendel, I. Kalvet, D. Hupperich, G. Magnin, and F. Schoenebeck, "Site‐Selective, Modular Diversification of Polyhalogenated Aryl Fluorosulfates (ArOSO 2 F) Enabled by an Air‐Stable Pd I Dimer", Angewandte Chemie International Edition, vol. 59, pp. 2115-2119, 2020. http://dx.doi.org/10.1002/anie.201911465
  • Optimization and Gram-Scale Preparation of S-Trifluoromethyl Sulfoximines and Sulfilimino Iminiums, Powerful Reagents for the Late Stage Introduction of the CF3 Group

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  • Regioselective Synthesis of Functionalized 3- or 5-Fluoroalkyl Isoxazoles and Pyrazoles from Fluoroalkyl Ynones and Binucleophiles

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