[rottenapples]

Could someone please help with the mechanism? Thanks in advance!

[Babcock_Hall]

It is a Forum Rule (see red link above) that you must provide your thoughts before we can help you.  I would start by assessing the overall transformation.   For example, are there any changes in the oxidation numbers of carbons?  Then I would look at the reagents for additional clues about the mechanism.  I would also think about whether or not this is a polar mechanism.