Under Lewis acidic conditions using Hf(OTf)(4), the aminomethylation of an indole derivative with a typical N,O-acetal preferentially produced kinetically favored N-aminomethylated indole derivatives instead of thermodynamically favored 3-aminomethylated indoles.
BURGER, U.;BRINGHEN, A. O.;WIRTHNER, PH. J.;SCHAERER, J. -C., HELV. CHIM. ACTA, 1985, 68, N 8, 2275-2281
作者:BURGER, U.、BRINGHEN, A. O.、WIRTHNER, PH. J.、SCHAERER, J. -C.
DOI:——
日期:——
Formation of the 5-Azoniafulvene Ion and its Benzo-annellated Analogue from N-<i>Mannich</i>Bases of Pyrrole and Indole
作者:Ulrich Burger、Alain O. Bringhen、Philippe J. Wirthner、Jean-Claude Schärer
DOI:10.1002/hlca.19850680822
日期:1985.12.18
N-atom rather than at the pyrrole ring. Spontaneous cleavage of the resulting quaternary acylammonium salts affords the 5-azoniafulvene ion (3). This higly reactive iminium ion, and its benzo-annellated analogue (4) can be trapped by electron rich aromatic compounds such as N-methylpyrrole or N,N-dimethylaniline. More elaborate N-Mannich bases are accessible by addition of indoles to enamines.