A Malaprade cleavage, a McMurry ring closure and an intramolecular aldol contraction of maslinic acid's ring A

A silica gel supported Malaprade cleavage of methyl maslinoate (-> 3) followed by a titanium-on-graphite sup-ported McMurry coupling was established to access a 2,12-terpenoid. The microwaves supported aldol reaction of dialdehyde 3 gave ring contracted 5. While parent maslinic acid is of minor cytotoxicity, improved cyto-toxicity was observed in SRB assays for 3 while ring contracted compound 5 was most cytotoxic for MCF-7 breast adenocarcinoma cells holding a low EC50 = 3.1 mu M.

Automated summary

A 2,12-terpenoid was synthesized using silica gel supported Malaprade cleavage and titanium-on-graphite supported McMurry coupling, with ring contracted compound obtained from microwaves supported aldol reaction. The ring contracted compound exhibited the highest cytotoxicity for MCF-7 breast adenocarcinoma cells.