Synthetic use of 1,1,2,2-tetraphenyldisilane for the preparation of biaryls through the intramolecular free radical ipso-substitution of N-(2-bromoaryl)arenesulfonamides
摘要:
Treatment of various N-methyl-N-(2-bromoaryl)arenesulfonamides (1a-g, 1i, and 1m) with 1,1,2,2-tetraphenyldisilane and AIBN under heating conditions gave the corresponding biaryl products (2a-g, 2i, and 2m) in moderate yields through the intramolecular radical ipso-substitution. However, N-H foe N-(2-brornoaryl)arenesulfonamides Ih and 2-bromoaryl arenesulfonate 1j did not give the corresponding biarys. 1,1,2,2-Tetraphenyldisilane is the most effective reagent for 1,5-ipso-substitution on the sulfonamides among typical radical reagents such as diphenylsilane, tributyltin hydride, tris(trimethylsilyl)silane, and 1,1,2,2-tetraphenyldisilane. Furthermore, 1,1,2,2 tetraphenyldisilane has the advantages of low toxicity, stability, and ease of preparation. (C) 2001 Elsevier Science Ltd. All rights reserved.
Let the sunshine in! Unactivated alkyl and aryl bromides underwent a light‐enabled reductive radical cyclization in the presence of a dimeric phosphine–gold complex as a photocatalyst (see scheme; X=C(CO2Et)2, NR, O). Sunlight can be used as the energy source for this simple and efficient radical reaction, which does not require potentially hazardous and toxic chemical reagents, such as organostannanes
让阳光照进来!未活化的烷基和芳基溴化物在二聚膦-金络合物作为光催化剂的情况下进行了光活化的还原性自由基环化反应(见方案; X = C(CO 2 Et)2,NR,O)。阳光可以用作此简单有效的自由基反应的能源,该自由基反应不需要潜在危险和有毒的化学试剂,例如有机锡和化学引发剂。
The invention relates to 2-(benzimidazol-1-yl)-acetamide bisaryl derivative having the general Formula I
wherein n is 0 or 1; Ar
1
represents a diradical derived from a 5- or-6-membered aromatic ring, optionally comprising 1-3 heteroatoms selected from N, O and S, said ring being optionally substituted with (C
1-4
)alkyl, (C
1-4
)alkyloxy, halogen, CF
3
or cyano; Ar
2
represents a 6-membered aryl ring, optionally comprising 1-3 nitrogen atoms, said ring being optionally substituted with 1-3 substituents selected from (C
1-4
)alkyl (optionally substituted with 1 or more halogens), (C
1-4
)alkyloxy (optionally substituted with 1 or more halogens), di(C
1-4
)alkylamino, halogen, CF
3
or cyano; or a pharmaceutically acceptable salt thereof; to pharmaceutical compositions comprising the same and to the use of said 2-(benzimidazol-1-yl)-acetamide bisaryl derivatives in the treatment of TRPV1 mediated disorders.
Synthesis of biaryls via intramolecular free radical ipso-substitution reactions
作者:Feroze Ujjainwalla、Maria Lucília E.N. da Mata、Andrew M.K. Pennell、Carmen Escolano、William B. Motherwell、Santiago Vázquez
DOI:10.1016/j.tet.2015.07.048
日期:2015.9
intramolecular freeradical [1,5]-ipso-substitution using sulfonamide and sulfonate derived tethering chains. The overall efficiency of the process is determined by appropriately positioned substituents on the aromatic acceptor ring. The extension of the process to benzylic sulfonates and their corresponding N-methylsulfonamide alternatives as substrates in potential [1,6]-ipso-substitution reactions leads
A novel route to biaryls via intramolecular free radical ipso substitution reactions
作者:William B. Motherwell、Andrew M. K. Pennell
DOI:10.1039/c39910000877
日期:——
A variety of usefully functionalised biaryls may be prepared under neutral conditions by an intramolecular free radicalipsosubstitution reaction at an sp2 sulphonyl substituted carbon atom; the overall efficiency of the process being determined both by the nature and number of atoms linking the two aromatic rings and by appropriately positioned substituents on the aromatic aceeptor ring.
A palladium-catalyzed chelation-assisted C–H olefination of 2-amino biaryls using readily available vinylsilanes as unactivated alkenes was developed to afford valuable arylated vinylsilanes with exclusive (E)-selectivities.