A CONVENIENT SYNTHESIS OF THE TOXICOPHORIC FURO[2,3-B]BENZOFURAN FRAGMENT PRESENT IN AFLATOXIN M1

A one-pot procedure involving four reaction steps (enolate formation, epoxidation, epoxide opening and deprotection), constitutes the key process for obtaining the hydroxyfuro[2,3-b]benzofuran moiety present in aflatoxin M1. The above sequential reactions led to the generation of the benzopyran aldehyde 8. As expected, this aldehyde underwent equilibration in solution giving rise to the epimeric mixture of dihydroxyfuro[2,3-b]benzofurans 9 as major components. This epimeric mixture was easily converted into the toxicophoric aflatoxin M1 fragment 10.