An efficient approach to access functionalized indole derivatives has been developed through Cu(OTf)2-catalyzed C3 aza-Friedel–Crafts alkylation of substituted indoles 5a–5m, N-methyl-pyrrole with linear N,O-acetals 4a–4l.
Novel Use of <i>N</i>-Benzoyl-<i>N,O</i>-acetals as <i>N</i>-Acylimine Equivalents in Asymmetric Heterocycloaddition: An Extended Enantioselective Pathway to β-Benzamido Aldehydes
For the first time, easily available N-(alpha-methoxyalkyl)amides were successfully used as synthetic equivalents of N-acylimines in an asymmetric heterocycloaddition process. The facial-controlled formation of 6-alkoxydihydrooxazines was thus achieved by SnCl4-promoted heterocycloaddition of (R)-O-vinyl pantolactone. By simple acidic hydrolysis of the crude heteroadducts, new beta-aryl- and beta-alkyl-substituted benzamido aldehydes were thus obtained in good overall yields with high enantioselectivities.
LOKENSGARD, J. P.;FISCHER, J. W.;BARTZ, W. J.;MEINWALD, J., J. ORG. CHEM., 1985, 50, N 26, 5609-5611
作者:LOKENSGARD, J. P.、FISCHER, J. W.、BARTZ, W. J.、MEINWALD, J.