Here, we report a highly effective and chemoselective method of preparing substituted indoles from (E)-2-nitropyrrolidinostyrenes via hydrogenation in the presence of a rhodium catalyst doped by additives such as Ni(NO3)2·6H2O, Fe(OAc)2 or Co(acac)3. These hydrogenation conditions may also be applied to other substrates. Aromatic nitro compounds and olefins can be selectively reduced in the presence
Phosphorus in organic synthesis. Acyloxyphosphonium salts as chemoselective acylating reagents
作者:Paul Frøyen
DOI:10.1016/s0040-4039(97)01172-6
日期:1997.7
Acyloxytriphenylphosphonium salts 1 prepared in situ react with a variety of aminophenols to give the corresponding amides in excellent yields. At −25° N-acylated products are formed exclusively, whereas at 0° some O-acylated products are observed. 1 is also a convenient trifluoroacetylating reagent.