Organofluorine compounds are widely used in many different applications, ranging from pharmaceuticals and agrochemicals to advanced materials polymers. It has been recognised for years that fluorine substitution can confer useful molecular properties such as enhanced stability hydrophobicity. Another impact of is influence the conformations organic molecules. The stereoselective introduction atoms therefore be exploited a conformational tool synthesis shape-controlled functional This review...

Rational expectations: Molecules containing six contiguous fluorine atoms along a carbon backbone have been synthesized in stereocontrolled manner. X-ray crystallography shows that the fluoroalkane can adopt helical or zigzag shape depending on stereochemical pattern (see structures). These findings are rationalized by simple effects associated with CF bonds. Detailed facts of importance to specialist readers published as "Supporting Information". Such documents peer-reviewed, but not...

Abstract New methods for enhancing the efficiency of peptide cyclization, and fine‐tuning conformations cyclic peptides, are valuable from a drug development perspective. Herein stereoselective fluorination is investigated as new strategy achieving these goals. Four vicinal difluorinated analogues natural heptapeptide unguisin A have been efficiently synthesized. The found to adopt dramatically different secondary structures, controlled by fluorine stereochemistry.

Human disease is heterogeneous, with similar phenotypes resulting from distinct combinations of genetic and environmental factors. Small-molecule profiling can address heterogeneity by evaluating the underlying biologic state individuals through non-invasive interrogation plasma metabolite levels. We analyzed profiles an oral glucose tolerance test (OGTT) in 50 individuals, 25 normal (NGT) impaired (IGT). Our focus was to elucidate processes. Although we initially found little overlap...

The conformational behaviour and GABA receptor activity of the different stereoisomers 2,3-difluoro-4-aminobutyric acid are described. Two enantiomeric GABAC-active ligands identified, one which is an agonist while other antagonist. results support existing QSAR model bioactive geometry at GABAC.

Shape control: Synthetic access has been achieved to all possible stereoisomers of the α,β-difluoro-γ-amino acid motif. These novel building blocks can readily be coupled other amino acids, and resulting peptides display unique conformational behavior depending on fluorine stereochemistry. The differences in peptide conformation rationalized terms various stereoelectronic effects associated with CF bonds.

This short review describes the development of new reagents and methods for deoxyfluorination phenols alcohols during period 2011 to 2017. Important advances in mechanistic understanding these processes are discussed. The continuing importance chemistry synthesis valuable target molecules is highlighted through case studies including examples 18F-radiosynthesis preparation exotic multifluorinated compounds. 1 Introduction 2 New Deoxyfluorination Reagents 3 Novel Applications ‘Legacy’...

Alkanes bearing multiple vicinal fluorine atoms at adjacent stereocenters may be considered intermediate between alkanes and perfluoroalkanes, as a class, their chemistry behavior remain to explored. We report here stereoselective synthesis of an all-syn four motif single enantiomer. The compound was amenable single-crystal X-ray analysis, the resulting structure displays gauche relationships all fluorines, consistent with effect, CF...HC hydrogen bonding fluoroalkyl chains.

Doing the twist: Differences in behavior between isomers of straight-chain alkanes bearing four vicinal fluorine atoms are revealed by conformational analyses (X-ray diffraction, NMR spectroscopy). For example, computational studies show that all-syn fluoroalkane (see picture, C gray, F green, H white) adopts a helical conformation, while anti-syn-anti isomer prefers to be linear. Supporting information for this article is available on WWW under...

The first synthesis of the γ-aminobutyric acid (GABA)-containing cyclic heptapeptide unguisin A is reported, confirming structure this natural product. Macrocyclization a flexible GABA-containing linear precursor found to proceed rapidly and in good yield.

Backbone-fluorinated amino acids exhibit unique conformational behaviour, and have potential utility as components of bioactive shape-controlled peptides. However, methods for the elaboration backbone-fluorinated thus far been limited to solution phase peptide coupling reactions. In this paper, protocols are developed that allow successful manipulation using Fmoc-strategy solid synthesis. To exemplify strategy, several fluorinated RGD analogues were synthesised in moderate good overall yields.

Backbone-homologated amino acids have been synthesized, containing three vicinal fluorine atoms placed stereospecifically along the carbon chain. Different trifluoro stereoisomers are found to contrasting conformations, consistent with known stereoelectronic effects associated C–F bonds.

Unguisin A (1) is a marine-derived, GABA-containing cyclic heptapeptide. The biological function of this flexible macrocycle obscure. Here we show that compound 1 lacks any detectable activity in antimicrobial growth inhibition assays, result runs contrary to previous report. However, find functions as promiscuous host molecule variety anion-binding interactions, with high affinity particularly for phosphate and pyrophosphate. We also series rigidified, backbone-fluorinated analogues...

Stereoselectively fluorinated analogues of the amino acid statine have been efficiently synthesized. The key step is an organocatalytic electrophilic fluorination a chiral β-oxygenated aldehyde, which provided test both diastereoselectivity and chemoselectivity. target were found to adopt unique conformations influenced by fluorine gauche effect, rendering them potentially valuable building blocks for incorporation into bioactive peptides.

Einfache Erklärung: Moleküle mit sechs aufeinanderfolgenden Fluoratomen an einer Kohlenstoffkette wurden stereokontrolliert hergestellt. Röntgenkristallographie ergab, dass das Fluoralkan je nach stereochemischem Muster eine Helix- oder Zickzackform annehmen kann (siehe Strukturen). Diese Befunde lassen sich einfachen stereochemischen Effekten der C-F-Bindungen erklären. Detailed facts of importance to specialist readers are published as ”Supporting Information”. Such documents...

Three unique diastereoisomers of 2,3,4,5-tetrafluorohexane have been prepared, compounds intermediate between hexane and perfluorohexane in their degree fluorination, they show very different conformational behaviour physical properties.