Reaction arrows were incorrectly placed within Scheme 3. Furthermore, the cyclization of intermediate 6 to give the product pyrrolocoumarin derivatives 4 was described as a 5-exo-trig process, both in Scheme 3 and the accompanying text, but should be referred to as a 5-exo-dig cyclization. The corrected Scheme 3 is given here.
Scheme 3 Probable mechanism of the amino-Claisen rearrangement
