I would not go with acetic anhydride or acetyl chloride since the work up will require excess of reagents. However I will look at new acetylating agent like
***N-Acyl 1,5-diazabicyclo[4.3.0]non-5-ene (DBN) tetraphenylborate salts as O-acylating agents, Tetrahedron Letters, Volume 53, Issue 32, 8 August 2012, Pages 4074-4076
James E. Taylor, Jonathan M.J. Williams, Steven D. Bull