{Despite|Regardless of|In spite of} the {general|common|basic} {high|higher} fluorophilicity of boron, {simple|easy|straightforward|basic|uncomplicated|very simple} organoboranes {such as|like|including|for example|for instance|which include} BEt3 and {3|three},5-(CF3)2C6H3–BPin are shown herein for {the first|the very first|the initial} time, to our {knowledge|understanding|information|expertise|know-how}, {to be|to become} {effective|efficient|successful|powerful|productive|helpful} phase-transfer catalysts for the fluorination of organohalides with CsF. {Significant|Substantial|Considerable|Important} chiral induction {during|throughout|in the course of|for the duration of|through} nucleophilic fluorination to {form|type|kind} b-fluoroamines {using|utilizing|making use of|employing|working with|applying} oxazaborolidine (CBS) (pre)catalysts and CsF also {can be|may be|could be|might be|is often|is usually} {achieved|accomplished}. Screening {different|various|distinct|diverse|unique|distinctive} boranes revealed a correlation {between|in between|among|amongst|involving} calculated fluoride affinity {of the|from the|in the|on the|with the|of your} borane and nucleophilic fluorination reactivity, with sufficent fluoride affinity {required|needed|necessary|essential|expected} for boranes to react with CsF and {form|type|kind} Cs[fluoroborate] salts, but {too|as well|also} {high|higher} a fluoride affinity {leading|top|major} to fluoroborates {that are|which are|which can be|which might be|that happen to be} poor at transferring fluoride to an electrophile. Fluoride affinity is only {one|1|a single|one particular} {component|element} controlling reactivity {in this|within this} context; {effective|efficient|successful|powerful|productive|helpful} fluorination also is dependent {on the|around the} ligation of Cs+ which effects the [Cs⋯F⋯BR3] interaction and {thus|therefore|hence|as a result} the B–F bond strength. {Effective|Efficient|Successful|Powerful|Productive|Helpful} ligation of Cs+ ({such as|like|including|for example|for instance|which include} by [2.{2|two}.2]-cryptand) weakens the Cs⋯FB interaction which strengthens the B–F bond – {thus|therefore|hence|as a result} disfavours fluoride transfer to an electrophile. Combined these findings enables optimal fluorination outcomes {to be|to become} {expected|anticipated} {using|utilizing|making use of|employing|working with|applying} robust ({to the|towards the|for the} fluorination {conditions|circumstances|situations}) boranes with fluoride affinity of ca. 110 kJ mol-1 (relative to Me3Si+) {under|below|beneath} {conditions|circumstances|situations} {where|exactly where} a signficant Cs⋯F–B interaction persists. (S)-Tetrahydrofuran-3-carboxylic acid structure H-Val-Ala-OH site PMID:23537004
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