SYNTHESIS OF BOTH TOP AND BOTTOM FRAGMENTS OF (-)-TALAROMYCIN-A THROUGH ENANTIOSPECIFIC AND DIASTEREOSELECTIVE ELABORATION OF ASYMMETRIZED TRIS(HYDROXYMETHYL)METHANE

Asymmetrized tria(hydroxymethyl)methane equivalents of general formula 5 have been employed as chiral building blocks for the enantiospecific and diastereoselective synthesis of both fragments 3 and 4, whose conversion into Talaromycin A was already reported. Preparation of bottom half fragment 3 was achieved through a ''protecting group-controlled'' stereoselective allylation of an asymmetrized bis(hydroxymethyl)acetaldehyde with allyltributyltin, while the top half fragment 4 was obtained in high overall yield by sequential elongation of two of the three synthetically equivalent masked hydroxymethyl group of 5, via nucleophilic substitution reactions.