Intramolecular Povarov reactions involving 3-aminocoumarins†
Abstract
A series of pentacyclic heterocyclic systems (15 examples, 69–89%) have been synthesized using intramolecular Povarov reactions involving 3-aminocoumarins and O-cinnamylsalicylaldehydes. The Povarov adducts are formed with high selectivity for the trans,trans relative stereochemistry in the newly-formed [6,6] fused ring system. One example of a Povarov adduct featuring a new [6,5] fused ring system is reported. In this case, cis,trans relative stereochemistry was preferred.