Total synthesis of lamellarin G trimethyl ether through enaminone cyclocondensation

A synthesis of pyrrolo[2,1-a]isoquinolines based on intramolecular condensation of an enaminone intermediate obtained by C-acylation of an N-alkylated 6,7-dimethoxy-1-methyl-3,4-dihydroisoquinolinium salt was developed. This methodology was further applied to the total synthesis of lamellarin G trimethyl ether from commercially available starting materials compatible with xylochemistry with an overall yield of 26% in 7 steps based on homoveratrylamine.