OBSERVATION OF 2,7-DISUBSTITUTION IN PALLADIUM CATALYSED DIRECTED C-H ACTIVATION OF INDOLES

摘要

In previous work, controlled C-H activation and catalytic Heck reaction at the 2-position of indole was demonstrated. This was achieved by means of a N-(2-pyridylmethyl) directing group. In the course of extending the initial observations it was discovered that the corresponding N-(1-isoquinolylmethyl)indole derivative was prone to a further oxidative Heck reaction giving rise to a 2,7-disubstituted product, which was characterised by NMR and X-ray analysis. The parent pyridine showed no tendency for a second substitution reaction at the indole 7-position, but the related N-(2-quinolylmethyl) derivative did. In the case of the corresponding 6-methylphenanthridinyl derivative, a novel oxidative C-C cleavage reaction was observed.