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This report describes the development of a Zn(OTf)2‐mediated method for converting α‐tertiary haloamides to the corresponding fluorine‐18 labelled α‐tertiary fluoroamides with no‐carrier‐added [18F]tetramethylammonium fluoride. 1,5,7‐Triazabicyclo[4.4.0]dec‐5‐ene is an essential additive for achieving high radiochemical conversion. Under the optimised conditions, radiofluorination proceeds at sterically hindered tertiary sites in high radiochemical conversions, yields, and purities. This method has been successfully automated and applied to access >200 mCi (>7.4 GBq) of several model radiofluorides. Mechanistic studies led to the development of a new, nucleophilic C−H radiofluorination process using N‐sulphonyloxyamide substrates. [ABSTRACT FROM AUTHOR]

The iridium‐catalysed borylation of aromatic C−H bonds has become the preferred method for the synthesis of aromatic organoboron compounds. The reaction is highly efficient, tolerant of a broad range of substituents and can be applied to both carbocyclic and heterocyclic substrates. The regioselectivity of C−H activation is dominated by steric considerations and there have been considerable efforts to develop more selective processes for less constrained substrates. However, most of these have focused on benzenoid‐type substrates and in contrast, heteroarenes remain much desired but more challenging substrates with the position and/or nature of the heteroatom(s) significantly affecting reactivity and regioselectivity. This review will survey the borylation of heteroarenes, focusing on the influence of steric and electronic effects on regiochemical outcome and, by linking to current mechanistic understandings, will provide insights to what is currently possible and where further developments are required. [ABSTRACT FROM AUTHOR]

A Cu‐mediated ortho‐C−H radiofluorination of aromatic carboxylic acids that are protected as 8‐aminoquinoline benzamides is described. The method uses K18F and is compatible with a wide range of functional groups. The reaction is showcased in the high specific activity automated synthesis of the RARβ2 agonist [18F]AC261066. Late‐stage fluorination: K18F is applied in a newly developed Cu‐mediated ortho‐C(sp2)−H radiofluorination of aromatic carboxylic acids that are protected as 8‐aminoquinoline benzamides. Fluorination of 18 examples in up to 62 % radiochemical yield and high specific activity is reported, including the automated synthesis of [18F]AC261066. [ABSTRACT FROM AUTHOR]