| Aryl methanes and aryl vinyl are widely used in natural compounds,optoelectronic materials,dyes and drugs intermediates because of their unique structure skeleton.It is one of the research hotspots in the field of synthesis to find an efficient and environment-friendly construction method.N-tosylhydrazones as the precursor of diazo compound,with a stable structure and high active become a research hotspot in the organic chemical neighbourhood.In the presence of metal-free,N-tosylhydrazones can be coupled with pinacolborane,arylboronic acid,alcohol and phenol;Also,it can be coupled with aryl halide,alkyne and arylboronic acid obtained alkenes by transition metal-catalyzed ?-H eliminate reaction.On the basis of predecessors' research work,the main work of this paper is exploring a series of methods to synthesis aryl methanes and aryl vinyl via study on the arone,tosylhydrazide with arylboronic acid/aryl halide one pot-multistep coupling reaction.The main content included four parts as follows:First,9-arylfluorenes were synthesized by metal-free reductive coupling of arylboronic acids and N-tosylhydrazones in situ.Initially,9-fluorenone(0.5 mmol)and phenylboronic acid(0.75 mmol)were chosen as model substrates for the reductive coupling in the presence of tosylhydrazide and potassium carbonate.The results showed that the combination of 9-fluorenone(0.5 mmol),tosylhydrazide(1.5 equiv.),phenylboronic acid(0.75 mmol),K2CO3(2 equivalents)at T1 = 80 °C(t1 = 2 hours)and T2 = 110 °C(t2 = 5 hours)in toluene(5 m L)were found to be the most suitable reaction conditions.Upon optimizing the reaction conditions,we further investigated the substrate scope of this one pot,two-step reductive coupling reaction.25 products were obtained in 29-93% yields and characterized by 1H NMR,13 C NMR,19 F NMR and HRMS(EI).Moreover,a gram-scale synthesis was performed to verify the practical application using this synthesis system.Fortunately,thte reaction was performed using 5 mmol of 9-fluorenone and 7.5 mmol(4-methoxyphenyl)boronic acid,and proceeded in 80% yield leading to 1.08 g of the desired product.Second,triarylmethanes were synthesized by metal-free reductive coupling of diaryl ketones,tosylhydrazide,and arylboronic acids.Initially,benzophenone(0.5 mmol),tosylhydrazide(1.5 equiv.),and phenylboronic acid(0.75 mmol)were chosen as model substrates for the reductive coupling in the presence of potassium carbonate.Finally,the combination of benzophenone(0.5 mmol),tosylhydrazide(1.5 equiv.),phenylboronic acid(0.75 mmol),K2CO3(3 equiv.)at T1 = 110 °C(t1 = 5 hours)and T2 = 150 °C(t2 = 5 hours)in toluene(3 m L)within 4? molecular sieve were found to be the optimal reaction conditions.Upon optimizing the reaction conditions,we further investigated the substrate scope of this one pot,two-step reductive coupling reaction,23 products were obtained in 17-82% yields and characterized by 1H NMR,13 C NMR,19 F NMR and HRMS(EI).Moreover,a gram-scale synthesis was performed to verify the practical application with this synthesis system.The reaction was performed using 7.5 mmol of benzophenone and 11.3 mmol [1,1'-biphenyl]-4-ylboronic acid,and the desired product was obtained in 56% yield.Third,a one-pot two-step reductive coupling between acetyl naphthalene derivatives,tosylhydrazide,and arylboronic acids,affording substituted 1(or 2)-(1-phenylethyl)naphthalenes in moderate-to-excellent yields,was reported.Notably,solvent played a crucial role in the coupling of 1-acetyl naphthalene derivatives(toluene)or 2-acetyl naphthalene derivatives(1,4-dioxane)as starting materials.Meanwhile,the scope of this one-pot coupling reaction was extended to 1(or 2)-naphthaldehyde substrates.A series of 2-(1-phenylethyl)naphthalene derivatives were obtained in 22-93% yields and characterized by 1H NMR?13C NMR?19F NMR and HRMS(EI).Particularly,the system was also suitable to synthesize 1(or 2)-(1-phenylethyl)naphthalenes on a multi-gram scale,and was applied in the synthesis of naphthylmethyl substituted carbazolyl compounds.Last,1,2-diarylethylenes were synthesized by Pd-catalyzed one-pot reaction of benzyl halides,tosylhydrazide,and aryl aldehydes.Initially,benzaldehyde,tosylhydrazide and benzyl bromide were used as model reaction in the presence of Pd(PPh3)4.The results showed that the combination of benzaldehyde(0.5 mmol)and benzyl bromide(0.6 mmol),tosylhydrazide(1.5 equiv.),Pd(PPh3)4(5 mol%)as the catalyst,Li OtBu(1.0 mmol)in toluene were found to be the most suitable reaction conditions.Upon optimizing the reaction conditions,we further investigated the substrate scope of this one pot,two-step reaction.23 products were obtained in 32-96% yields and characterized by 1H NMR and 13 C NMR.Moreover,a gram-scale synthesis was performed to verify the practical application using this system.The reaction was performed using 7.5 mmol of benzaldehyde,Ts NHNH2(1.5 equiv.)and 9.0 mmol benzyl bromide,and proceeded in 84% yield leading to 1.14 g of the desired product.The synthetic potential of this methodology was illustrated by a very concise formal synthesis of the DMU-212 through the cross-coupling of 4-methoxybenzaldehyde N-tosylhydrazones with 5-(bromomethyl)-1,2,3-trimethoxybenzene under standard conditions,and gave the desired product in yield of 71%.In summary,this study is based on N-tosylhydrazones as intermediate coupling with arylboronic acid and halohydrocarbon,respectively.A series of aryl methanes and aryl vinyl were synthesized.In particular,aryl methanes and aryl vinyl derivatives were obtained by simple,effective,sustainable,and facile method,which provided an important supplement and perfection to C–C and C=C bond formation. |
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