Hmc. Ferraz et al., Synthesis of N-substituted pyrrole and tetrahydroindole derivatives from alkenyl beta-dicarbonyl compounds, TETRAHEDRON, 55(36), 1999, pp. 10915-10924
The iodocyclization of a series of alknyl-substituted beta-enamino esters a
nd ketones, followed by base-promoted dehydroiodination, led to the formati
on of the corresponding pyrrole or tetrahydroindole derivatives. In the abs
ence of base, the iodo-beta-enamino esters 5 and 7 underwent spontaneous ar
omatization after dehydroiodination, furnishing the 4, 5, 6, 7-N-substitute
d-tetrahydroindoles 19 and 20. All the elimination reactions proceeded smoo
thly, in yields ranging from 71% to 99%. Starting from the beta-allyl-dimed
one 21, it was possible to prepare the oxotetrahydroindole 24, in moderate
overall yield. (C) 1999 Elsevier Science Ltd. All rights reserved.