Reactions of Perfluorinated Alkenyl‐, Alkynyl‐, Alkyltrifluoroborates, and Selected Hydrocarbon Analogues with the Halogenating Agents Hal₂ (Hal = F, Cl, Br), “BrF” (BrF₃–Br₂ 1:1), and ICl

Abstract

Reactions of [Bu 4 N][RBF 3 ] [R = C n F 2n+1 CF=CF (cis, trans), CF 2 =CF, CF 2 =C(CF 3 ), trans-C 4 H 9 CF=CF, trans-C 6 H 5 CF=CF, C 4 H 9 CH=CH (cis, trans), CF 3 CϵC, and C 4 H 9 CϵC] with chlorine, bromine, BrF 3 + Br 2 (as equivalent of "BrF"), and ICl in solution (CH 2 Cl 2 , CHCl 3 , CF 3 CH 2 CF 2 CH 3 ) led to 1,2-addition of halogen and/ or replacement of boron by halogen (halodeboration). The reaction of [Bu 4 N][CF 3 CϵCBF 3 ] with less than equimolar amounts of diluted fluorine (5 %) in 1,1,1,3,3-pentafluorobutane (PFB) showed only [Bu 4 N][CF 3 CF 2 CF 2 BF 3 ] as fluorine addition product besides extensive Scheme 5. Scheme 6. Scheme 7.Reaction of K[CF 2 =CFBF 3 ]: Chlorine (4.5 mmol) was bubbled into a stirred suspension of K[CF 2 =CFBF 3 ] (173 mg, 0.92 mmol) in CH 2 Cl 2

Divergent, Stereospecific Mono‐ and Difluoromethylation of Boronic Esters

“…It should be noted that 2 represents a unique example of an isolated alkyl α-fluoroboronic ester outside the tetracoordinated MIDA and trifluoroboronates. [24][25][26] The ready preparation of these intermediates will now enable their broader applications in synthesis. Having identified a suitable reagent and conditions for homologation, our attention focused on the subsequent protodeboronation step which would give access to the CH2F functionality.…”

Divergent, Stereospecific Mono‐ and Difluoromethylation of Boronic Esters

“…Fluoroboronic ester 2 was unstable to chromatography, but a simple aqueous work up gave material of sufficient purity to be used directly in the subsequent transformations. It should be noted that 2 represents a unique example of an isolated alkyl α‐fluoroboronic ester outside the tetracoordinated MIDA and trifluoroboronates . The ready preparation of these intermediates will now enable their broader applications in synthesis.…”

“…It should be noted that 2 represents a unique example of an isolated alkyl a-fluoroboronic ester outside the tetracoordinated MIDA and trifluoroboronates. [24][25][26] The ready preparation of these inter-mediates will now enable their broader applications in synthesis.…”