NEW FORMAL [3+3]CYCLOADDITION REACTIONS OBETWEEN 3-CARBOXICUMARINS AND ENAMINONES IN THE SYNTHESIS OF CARBO- AND POLYFUNCTIONALIZED HETEROCYCLES
Enaminones, coumarins, reactivity.
In this work, the study of the reactivity of coumarino-3-carboxylic acids against the five-membered cyclic enaminones in formal aza-[3+3] cycloaddition reactions was carried out for the first time. Thus, 08 new polyfunctionalized indolizidine core were obtained with satisfactory yield (47-94%) and 03 new dihydropyridones in yields between 59 and 68% were obtained. Additionally, from synthetic applications of suitable indolizidinones, it was possible to access new coumarin-indolizidinic hybrids via trans-ring reactions, promoted by Fe(acac)3 and oxidative aromatization reactions, catalyzed by Pd/C (10 mol%). In addition, the reactivity of coumarin-3-carboxylic acids to secondary acyclic enaminones was investigated to obtain 10 unprecedented cyclohexenones, with an adequate level between 70 and 99%. In addition, two new azabicycles were accessed from reactions between primary acyclic enaminones and coumarin-3-carboxylic acid.