Both of these were on my desk this morning. One was given to a PhD student by a certain eminent professor who is still in the lab! Can you work out the mechanisms?
I did one fairly quickly, the other I still haven’t worked out.
Email me your solutions at theorganicsolutionblog at gmail dot com or tweet me @jessthechemist
UPDATE: This problem comes for an OPRD paper: http://pubs.acs.org/doi/pdf/10.1021/op3002933. Take a look and see if you agree with their mechanism.