Experimental

At   0oC,   26mg   (100   micromoles)   of   compound   40   was   dissolved   in   anhydrous   CH2Cl2   under   Argon.   Also,   50   mg   of   4   Å molecular   sieve was   added   to   the   solution   and   the   mixture   was   stirred   while refluxing for   1   hour.   While   this   was   occurring, dimethyldioxirane   in   acetone (120   micromoles,   1.2   eq)   was   prepared   and   injected   dropwise   to   the   refluxing   mixture.   After   10   minutes,   the   system   was flushed with   a   continuous   flow   of   argon   .   Next,   2mL   of anhydrous   ether was   added   to   the   residue. Boron   trifluoride   etherate (30microliters,   3   eq)   was   added   slowly   and   consecutively   to   the   reaction.   After   15   minutes,   the   reaction   was   quenched   with   saturated   NaHCO3,   extracted   with   ethyl   acetate,   and   dried   over   MgSO4.   Then gravity   filtration was   performed   and   the   remaining   solvent   was   removed   under   reduced   pressure.   The   residue   was   purified   using flash   chromatography to   provide   a   white   solid   (22mg,   82%   yield)   as   1:1   C-‐16 epimers.   One   of   the   epimers   was   isolated   and characteri
zed.
EXPERIMENTAL
