Recyclable Trifluoromethylation Reagents from Fluoroform

Abstract

We present a strategy to rationally prepare CF transfer reagents at ambient temperature from HCF We demonstrate that a highly reactive CF adduct can be synthesized from alkali metal hydride, HCF, and borazine Lewis acids in quantitative yield at room temperature. These nucleophilic reagents transfer CF to substrates without additional chemical activation, and after CF transfer, the free borazine is quantitatively regenerated. These features enable syntheses of popular nucleophilic, radical, and electrophilic trifluoromethylation reagents with complete recycling of the borazine Lewis acid.

On the Structure of [K(crypt‐222)]+

“…Deprotonation of CHF 3 with CH 3 S(O)/ DMSO within minutes (top) and lack of any transformations of [K(crypt‐222)] + in the presence of CD 3 S(O)/(D 6 ) DMSO after 5 days (bottom) under similar conditions.…”

“…Likewise, while CHF 3 is quickly deprotonated with dimsyl at ambient temperature and even below, neither incorporation of deuterium into [K(crypt‐222)] + , nor any other observable ( 1 H‐NMR) transformation of the cation took place in the presence of CD 3 S(O)CD 2 K in (D 6 )DMSO (p K a DMSO = 35.1) after 5 days at 23 °C ( Scheme ).…”

“…Scheme 6. Deprotonation of CHF 3 with CH 3 S(O)CH À 2 /DMSO within minutes [44] (top) and lack of any transformations of [K (crypt-222)] + in the presence of CD 3 S(O)CD À 2 /(D 6 )DMSO after 5 days (bottom) under similar conditions. 8 As unsurprisingly, there have been no literature reports on H/D exchange reactions of [K(crypt-222)] + or isolation/ detection of its conjugated base.…”

“… While no p K a data for CHF 3 has been reported in DMSO, the value of 26 has been obtained in DMF, another member of the family of aprotic dipolar solvents. Our estimate of p K a DMSO (DMSO ≈ CHF 3 ) is based on this data as well as the fact that dimsyl in DMSO readily deprotonates CHF 3 at room temperature and even below …”

Ring Expansion, Photoisomerization, and Retrocyclization of 1,4,2‐Diazaboroles

“…[1] Since the landmark study reported by Dewar et al in 1958, [2] B,Nanalogues of benzene (C 6 H 6 ), namely,azaborinines,have been studied extensively. [3] Not only their unique fundamental electronic structures but also their broad potential for practical use in coordination chemistry, [4] materials science, [5] and biomedical chemistry [6] have been described to date.M oreover,i th as been demonstrated that azaborinines can be employed as ac hemical for hydrogen storage, [7] as ynthon in organic molecular synthesis, [8] as mall-molecule activator, [9] and ap recatalyst, [10] thus explicitly indicating their diverse utility in various applications.S everal azaborole derivatives containing an aromatic B,Nf ive-membered-ring framework have also been reported since the 1960s. [11] In contrast to azaborinines, however, reported applications of azaboroles are still limited mainly to their use as ligands for metal complexes,although it has been shown that some exhibit unique biological activity and optoelectronic properties.…”