Synthesis of biaryls via intramolecular free radical ipso-substitution reactions
A variety of functionalised biaryls and heterobiaryls are prepared by intramolecular free radical [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 mainly to the alternative [1,7] addition products.
Ujjainwalla, Feroze,Da Mata, Maria Lucília E.N.,Pennell, Andrew M.K.,Escolano, Carmen,Motherwell, William B.,Vázquez, Santiago
p. 6701 - 6719
(2015/08/24)
Highly specific N-monomethylation of primary aromatic amines
A synthetic methodology for the specific conversion of primary aromatic amines into their N-monomethyl derivatives under very mild conditions is presented. Anilines are treated with 4-nitrobenzenesulfonyl (nosyl) chloride to generate the corresponding sulfonamides 2 in high yields. The subsequent N-methylation reaction of the sulfonamides 2 with a solution of diazomethane is rapid and quantitative. Removal of the nosyl protecting group is readily carried out using the reagent system mercaptoacetic acid/1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) affording the N-monomethylated aromatic amines 4. The procedure is convenient, efficient, and gives rise to the N-monomethyl-anilines exclusively.
Le Pera, Adolfo,Leggio, Antonella,Liguori, Angelo
p. 6100 - 6106
(2007/10/03)
More Articles about upstream products of 900537-30-6