Efficient conversion of aucubin into 6-epi-aucubin

Selective deprotection of peracetylaucubin (3) by use of KCN led to 6-O-acetylaucubin (4), which was readily converted into 2',3',4',6', 10-penta-O-benzoylaucubin (7). Configuration inversion performed on 7, using a modified Mitsunobu reaction, followed by deprotection, afforded 6-epi-aucubin (2).