Synthesis of enantiopure (S)-indolylglycine by organocatalyzed Friedel-Crafts alkylation of indole
Tritylsulfenyl- and 2-nitrophenylsulfenyl-substituted glyoxyl imines were used in chiral phosphoric acid catalyzed Friedel-Crafts (FC) reactions with indole. High yields and ee values ranging from 86 % for Nps-protected (S)-indolylglycine to 88 % for Trs-
Wanner, Martin J.,Hauwert, Peter,Schoemaker, Hans E.,De Gelder, Rene,Van Maarseveen, Jan H.,Hiemstra, Henk
p. 180 - 185
(2008/09/18)
Convenient Syntheses of 2-Nitrophenylsulfen-(NPS-)imines by Oxidation of NPS-Protected Amines and Amino Acid Derivatives
2-Nitrophenylsulfenimines 2 of large structural variety are easily available from 2-nitrophenylsulfenamides 1, by direct and indirect electrochemical oxidation or by using stoichiometric amounts of a triarylamine radical cation salt.In most cases the dire