Total Synthesis of (+)-Polyoxin J.

Abstract

Stereoselective total synthesis of (+)-polyoxin J is described. The synthesis was achieved in a convergent manner by coupling protected thymine polyoxin C (19) and 5-O-carbamoyl polyoxamic acid 27 and subsequent removal of the protecting groups. The key steps of the synthesis of protected thymine polyoxin C involved the stereoselective electrophilic epoxidation of E-allyl alcohol 7 derived from isopropylidene D-ribose derivative 5, followed by regioselective epoxide opening of 8 and conversion of resulting azido diol 9 to protected thymine polyoxin C (19). Protected polyoxamic acid 27 was synthesized stereoselectively by utilizing Sharpless epoxidation of tartrate-derived allylic alcohol 20 followed by a regioselective epoxide ring opening with diisopropoxytitanium diazide.