75070-85-8Relevant academic research and scientific papers
C-H and C-F bond activation reactions of pentafluorostyrene at rhodium complexes
Xu, Conghui,Talavera, Maria,Sander, Stefan,Braun, Thomas
supporting information, p. 16258 - 16267 (2019/11/13)
The rhodium(i) complexes [Rh(Bpin)(PEt3)3] (1), [Rh(H)(PEt3)3] (5) and [Rh(Me)(PEt3)3] (14) were employed in reactions with pentafluorostyrene affording coordination of the olefin and C-F o
C-H and C-F Bond Activations at a Rhodium(I) Boryl Complex: Reaction Steps for the Catalytic Borylation of Fluorinated Aromatics
Kall?ne, Sabrina I.,Teltewskoi, Michael,Braun, Thomas,Braun, Beatrice
, p. 1156 - 1169 (2015/04/27)
Treatment of the rhodium(I) boryl complex [Rh(Bpin)(PEt3)3] (1, pin = pinacolato = O2C2Me4) with pentafluorobenzene, 1,3,5-trifluorobenzene, 1,3-difluorobenzene, or 3,5-difluoropyridine led to C-H activation reactions to give the aryl complexes [Rh(C6F5)(PEt3)3] (4), [Rh(2,4,6-C6F3H2)(PEt3)3] (5), [Rh(2,6-C6F2H3)(PEt3)3] (6), and [Rh{4-(3,5-C5NF2H2)}(PEt3)3] (8). For 5, 6, and 8 consecutive reactions with in situ generated HBpin occurred to yield [Rh(H)(PEt3)3] (7) and boronic esters. The boryl complex 1 gave with hexafluorobenzene or perfluorotoluene the C-F activation products [Rh(C6F5)(PEt3)3] (4) and [Rh(4-C6F4CF3)(PEt3)3] (9), respectively. The complexes 5, 6, and 9 react with B2pin2 to yield 1 and boronic ester derivatives. On the basis of these stoichiometric reactions catalytic C-H and C-F borylation reactions using 1 or 7 were developed to generate 2-Bpin-1,3,5-C6F3H2, 2-Bpin-1,3-C6F2H3, and 4-Bpin-C6F4CF3 from 1,3,5-trifluorobenzene, 1,3-difluorobenzene, or perfluorotoluene and B2pin2. On treatment of pentafluoropyridine with B2pin2 in the presence of 1 or 7 as catalyst 2-Bpin-C5NF4 was synthesized by C-F borylation at the 2-position. Using 2,3,5,6-tetrafluoropyridine, B2pin2, and catalytic amounts of 7 led to a C-H borylation reaction at the 4-position. 4-Bpin-C5NF4 can also be prepared by the reaction of 2,3,5,6-tetrafluoropyridine with stoichiometric amounts of HBpin or by the reaction of pentafluoropyridine with an excess of HBpin in the presence of 7, whereas the reaction of pentafluoropyridine with stoichiometric amounts of HBpin and 5 mol % 7 resulted in the formation of 2,3,5,6-tetrafluoropyridine via hydrodefluorination reaction at the 4-position. This regioselectivity contrasts the borylation of pentafluoropyridine at the 2-position with 1 as catalyst. Overall, the obtained fluorinated aryl boronic ester derivatives might serve as versatile building blocks. (Chemical Equation Presented).
Versatile reactivity of a rhodium(i) boryl complex towards ketones and imines
Kallaene, Sabrina I.,Braun, Thomas,Braun, Beatrice,Mebs, Stefan
, p. 6786 - 6801 (2014/05/06)
The rhodium(i) boryl complex [Rh(Bpin)(PEt3)3] (1) reacts with the ketones α,α,α-trifluoroacetophenone and 9-fluorenone by insertion of the CO bond to give [Rh{η3-C(CF 3)(OBpin)C6H5}(PEt3)2] (4) and [Rh{η5-C13H8(OBpin)}(PEt 3)2] (6), whereas the reaction with acetophenone leads to the formation of [Rh(H)(PEt3)3] (2), [Rh(OBpin)(PEt 3)3] (3) and (E)-(Ph)CHCHBpin. Treatment of 1 with ketimines generates [Rh{η3-C6H5C(Ph)N(Ph) (Bpin)}(PEt3)2] (7), [Rh{(η3-C 12H8)N(Ph)(Bpin)}(PEt3)2] (8) or [Rh{CPh2N(H)(Bpin)}(PEt3)2] (9). The insertion of aldimines into the Rh-B bond gives access to [Rh[η3- CH{N(C6H13)Bpin}C6H5](PEt 3)2] (11) or [Rh[η3-CH{N(Ph)Bpin}C 6H5](PEt3)2] (12). The latter is converted into the C-H activation product [Rh{(C6H 4)-o-N(Bpin)(CH2Ph)}(PEt3)3] (13). Complex 13 reacts with B2pin2 to yield the boryl complex 1 and the amine PhCH2N(Bpin)(C6H4-o-Bpin). This journal is the Partner Organisations 2014.
Catalytic borylation of SCF3-functionalized arenes by rhodium(I) boryl complexes: Regioselective C-H activation at the ortho-position
Kallaene, Sabrina I.,Braun, Thomas
supporting information, p. 9311 - 9315 (2014/11/07)
An unprecedented reaction pathway for the borylation of SCF 3-containing arenes using [Rh(Bpin)(PEt3)3] (pin=pinacolato) is reported. Catalytic processes were developed and the functionalizations proceed under mild reaction conditions. The C-H activations occur with a unique regioselectivity for the position ortho to the SCF 3 group, which apparently serves as directing group. Borylated SCF3 compounds can serve as versatile building blocks. SCF 3 building blocks: A unique reaction route allows access to SCF 3-functionalized arenes, which are borylated at the ortho-position. The functionalization proceeds by C-H borylation with [Rh(Bpin)(PEt 3)3] (pin=pinacolato), and the SCF3 group likely serves as directing group. The generated borylated SCF3 compounds are versatile building blocks for further transformations.
Synthesis of rhodium(I) boryl complexes: Catalytic N-H activation of anilines and ammonia
Teltewskoi, Michael,Kallaene, Sabrina I.,Braun, Thomas,Herrmann, Roy
, p. 5762 - 5768 (2013/12/04)
The treatment of the rhodium methyl complex [Rh(Me)(PEt3) 3] (1) with diboranes B2[(OR)2]2 gave the 16-valence-electron rhodium(I) boryl complexes [Rh{B(OR) 2}(PEt3)3] [2: (OR)2 = pin = pinacolato, O2C2Me4; 3: (OR)2 = cat = catecholato, O2C6H4; 4: (OR)2 = O2C5H10]. The reactions of 2 and 4 with anilines yielded the amidoboranes HN[B(OR)2](R′) [6: B(OR) 2 = Bpin, R′ = C6F5; 7: B(OR)2 = Bpin, R′ = Ph; 8: B(OR)2 = BO2C5H 10, R′ = Ph] and the rhodium hydrido complex [Rh(H)(PEt 3)3] (5) by N-H activation. The addition of ammonia to 2 resulted in the generation of the amine HN(Bpin)2 (9) as well as 5. The amidoboranes 6, 7, and 9 can also be synthesized catalytically with turnover numbers of 10 for 9 and 8 for 6 and 7. Sixteen-electron RhI boryl complexes are synthesized and used for N-H bond activation reactions of anilines. The treatment of [Rh(Bpin)(PEt3)3] (HBpin = pinacolborane) with NH3 yields the diborylamine HN(Bpin)2. The stoichiometric conversion led to the development of a new catalytic process, and [Rh(Bpin)(PEt3)3] is used as a catalyst to convert NH3 and B2pin2 into HN(Bpin) 2 at room temperature. Copyright
Transfer of amido groups from isolated rhodium(I) amides to alkenes and vinylarenes
Zhao, Pinjing,Krug, Christopher,Hartwig, John F.
, p. 12066 - 12073 (2007/10/03)
The reaction of monomeric and dimeric rhodium(l) amido complexes with unactivated olefins to generate imines is reported. Transamination of {(PEt 3)2RhN(SiMePh2)2} (1a) or its -N(SiMe3)2 analogue 1b with p-toluidine gave the dimeric [(PEt3)2Rh(M-NHAr)]2 (Ar = p-tolyl) (2a) in 80% isolated yield. Reaction of 2a with PEt3 generated the monomeric (PEt3)3Rh(NHAr) (Ar = p-tolyl) (3a). PEt 3-ligated arylamides 2a and 3a reacted with styrene to transfer the amido group to the olefin and to form the ketimine Ph(Me)-C=N(p-tol) (4a) in 48-95% yields. The dinuclear amido hydride (PEt3)4Rh 2(μ-NHAr)(μ-H) (Ar = p-tolyl) (5a) was formed from reaction of 2a in 95% yield, and a mixture of this dimeric species and the (PEt 3)nRhH complexes with n = 3 and 4 was formed from reaction of 3a in a combined 75% yield. Propene reacted with 2a to give Me 2C=N(p-tol) (4b) and 5a in 90 and 57% yields. Propene also reacted with 3a to give 4b and 5a in 65 and 94% yields. Analogues of 2a and 3a with varied electronic properties also reacted with styrene to form the corresponding imines, and moderately faster rates were observed for reactions of electron-rich arylamides. Kinetic studies of the reaction of 3a with styrene were most consistent with formation of the imine by migratory insertion of olefin into the rhodium-amide bond to generate an aminoalkyl intermediate that undergoes β-hydrogen elimination to generate a rhodium hydride and an enamine that tautomerizes to the imine.
C-F activation and hydrodefluorination of fluorinated alkenes at rhodium
Noveski, Daniel,Braun, Thomas,Schulte, Miriam,Neumann, Beate,Stammler, Hans-Georg
, p. 4075 - 4083 (2007/10/03)
Reaction of [RhH(PEt3)4] (9) with hexafluoropropene (1) affords the C-F activation product [Rh{(Z)-CF=CF(CF3)}(PEt3)3] (4) as well as Et3P(F){(Z)-CF=CF(CF3)} (11). In contrast, addition of (E)-1,2,3,3,3-pentafluoropropene (8) to 9 yields [Rh{(E)-C(CF3)=CHF}(PEt3)3] (12) together with [RhF(PEt3)3] (6) and (Z)-1,3,3,3-tetrafluoropropene (10). Treatment of 12 with hydrogen effects the formation of 1,1,1-trifluoropropane (2) and the fluoro compounds [RhF(PEt3)3] (6) and cis-mer-[Rh(H)2F(PEt3)3] (7). On treatment of 6 or of a mixture of 6 and 7 with HSiPh3 the complexes [RhH(PEt3)3] (3) and cis-fac-[Rh(H)2(SiPh3)(PEt3)3] (13) are obtained. Both compounds are capable of the C-F activation of hexafluoropropene (1) to afford 4. The molecular structure of complex 13 has been determined by X-ray crystallography.
