This recieved little attention in the serious chem forum, but Sam posted this patent U.S. 3365499.
http://l2.espacenet.com/espacenet/bnsviewer?CY=gb&LG=en&DB=EPD&PN=US3365499&ID=US+++3365499A1+I+ (http://l2.espacenet.com/espacenet/bnsviewer?CY=gb&LG=en&DB=EPD&PN=US3365499&ID=US+++3365499A1+I+)
It is worth investigating it involves using solvents like DMF, or DMSO and titrating the mixture with water, instead of alkene to get a higher yeild using the Benzo wacker.
Check it out.
Proper patent linking, see the FAQ: Patent US3365499 (http://l2.espacenet.com/dips/viewer?PN=US3365499&CY=gb&LG=en&DB=EPD)