Fluorous tags, like the amine protecting group F17 Boc-ON, provide a lot of functions. They can be attached and removed just like non-fluorous tags and similarly protect functional groups. While attached to your molecule, the fluorous tag also allows for quick and easy intermediate purification. By choosing fluorous tags, you already know how to purify your desired compound before you even perform the synthesis — no method development needed. The tag adds valuable information to your molecule.
The Curran Group, with its fluorous mixture synthesis natural product structure elucidation work, has taken this idea one step further. In addition to pre-determining the purification method, they encode isomeric configuration data with their use of fluorous tags. This is clearly seen in their recent JOC article, “Assignment of the Structure of Petrocortyne A by Mixtures Synthesis of Four Candidate Stereoisomers” (doi: 10.1021/jo100115h). Here’s a quote that defines their fluorous tag strategy (emphasis added):
[W]e will be able to resolve the final mixture into its four individual components by demixing, and we will know which isomer is which by reading (identifying) the tags. In essence, a bit of extra work in the beginning could pay big dividends at the end because there are built-in solutions to the problems of separation and identification.
Couldn’t have said it better myself. But let’s not forget the synthetic savings inherent in fluorous mixture synthesis. By working with mixtures, the researchers were able to leverage their synthetic effort to produce more compounds. More compounds plus added information – that’s a powerful combination made possible by fluorous tags.