Synthesis of β-Aryl Ketones by Tetraphosphine/Palladium Catalyzed Heck Reactions of 2- or 3-Substituted Allylic Alcohols with Aryl Bromides (original) (raw)
Related papers
Tetrahedron, 2006
Through the use of [PdCl(C 3 H 5 )] 2 /cis,cis,cis-1,2,3,4-tetrakis(diphenylphosphinomethyl)cyclopentane as a catalyst, a range of aryl bromides undergoes Heck reaction using 2-or 3-subtituted allylic alcohols. With these sterically congested alkenes, the selective formation of b-aryl ketones was observed when appropriate reaction conditions were used. The influence of the functional group on the aryl bromide and of the base on the selectivity is remarkable. With several substrates, much higher selectivities were obtained using NaHCO 3 instead of K 2 CO 3 as base. Furthermore, this catalyst can be used at low loading with several substrates. q
Tetrahedron Letters, 2004
cis,cis,cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/[PdCl(C 3 H 5 )] 2 efficiently catalyses the Heck reaction of alk-1-en-3-ol with a variety of aryl bromides. In the presence of hex-1-en-3-ol or oct-1-en-3-ol, the b-arylated carbonyl compounds were selectively obtained. Linalool and 2-methylbut-3-en-2-ol led to the corresponding 1-arylalk-1-en-3-ol derivatives. Turnover numbers up to 69,000 can be obtained for this reaction. A minor electronic effect of the substituents of the aryl bromide was observed. Similar reaction rates were observed in the presence of activated aryl bromides such as bromoacetophenone and deactivated aryl bromides such as bromoanisole.
Tetrahedron Letters, 2003
cis,cis,cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/[PdCl(C 3 H 5 )] 2 system catalyses efficiently the Heck reaction of aryl halides with linear alkenes such as pent-1-ene, oct-1-ene or dec-1-ene. Selectivities up to 70% in favour of E-1-arylalk-1-ene isomers can be obtained. In the presence of cyclic alkenes the selectivities of the reactions strongly depends on the ring size. Addition to cyclohexene or cycloheptene led mainly to 1-arylcycloalk-3-ene derivatives. On the other hand, addition to cyclooctene led to 1-arylcycloalk-1-ene adducts.
Pd-catalyzed Heck reactions of aryl bromides with 1,2-diarylethenes
Journal of the Brazilian Chemical Society, 2011
Um sistema catalítico composto por Pd(OAc) 2 e P(o-tol) 3 foi aplicado na reação de Heck entre brometos de arila e diariletenos. Utilizando-se K 2 CO 3 como base e DMF como solvente, olefinas triarilsubstituídas foram obtidas com rendimentos de bons a excelentes. Brometos de arila com substituintes eletroretiradores foram menos ativos para a reação de acoplamento Heck e levaram à formação de produto de homoacoplamento em quantidades substanciais, indicando que a adição oxidativa não deve ser a etapa lenta da reação. A presença de substituintes no diarileteno afetou drasticamente a seletividade da reação. Realizou-se também a dupla arilação do estireno, levando diretamente à olefina triarilsubstituída, com rendimento de 73%. A catalytic system composed of Pd(OAc) 2 and P(o-tol) 3 was found to be effective for the Heck reaction of aryl bromides with diarylethylenes. Using K 2 CO 3 as a base and DMF as a solvent, trisubstituted olefins were obtained in good to excellent yields. Aryl bromides containing an electron-withdrawing group in para position were less reactive for the Heck coupling reaction and gave substantial amount of homocoupling by-product suggesting that oxidative addition is not the rate-determining step. Electron withdrawing group substituent in the para position of stilbene affects the regioselectivity of the reaction. In this case, the phenyl group from the Ph-Pd complex migrates preferentially to the same carbon of the double bond to which the phenyl is bonded. Finally, a one pot sequential double Heck arylation of styrene was performed, giving trisubstituted olefin with an overall yield of 73%.
Heck-type reactions of allylic alcohols
Journal of Molecular Catalysis A: Chemical, 2008
Various conditions have been tested to obtain efficiently 2-methyl-1-indanone via the Pd-catalyzed 5-endo-trig cyclization of 1-(o-bromophenyl)-2-methylprop-2-en-1-ol. High yield (97%) was obtained at 120 • C in DMF with Pd(OAc) 2 /cinchonine as the catalytic system and NaHCO 3 as the base. Use of this procedure for the synthesis of other substituted indanones led to lower yields but replacing thermal heating by microwave heating improved greatly the results.
Heck reaction with heteroaryl halides in the presence of a palladium-tetraphosphine catalyst
Tetrahedron Letters, 2002
cis,cis,cis-1,2,3,4-Tetrakis(diphenylphosphinomethyl)cyclopentane/ 1 2 [PdCl(C 3 H 5 )] 2 system catalyses efficiently the Heck reaction of heteroaryl halides with n-butyl acrylate, styrene, vinylpyridine and vinyl ether derivatives. High turnover numbers can be obtained for the reactions with halo pyridines, quinolines, furans or thiophenes.