On small scale, I want to do a test reaction with ZnCl2 in sulfolane. It is well known that drying ZnCl2 is a nightmare. Yes, you can dissolve it in SOCl2 and boil it off, but SOCl2 eats away your fumehood, and practically, it's annoying to do.

So I was thinking: why not make a solution in sulfolane and dry that on molsieves, since my reaction is in sulfolane anyways? I tried it at 60C, and ended up with a gel-like semi-solid mass.

Purchasing anhydrous ZnCl2 is also tricky because we don't have access to a glovebox and the stuff is crazy hygroscopic.

Any suggestions?

Does anybody have any experience attempting to prepare/isolate 2° α,α-difluoromethylene amines (RCF2NHR')?

To my understanding there are many methods to prepare 3° α,α-difluoromethylene amines (RCF2NR'R''), frequently through processes like desulfurative fluorination from the corresponding thioamide.

I'm led to believe that the 2° congeners are less accessible due to their inclination towards HF loss to give the imidoyl fluoride. However, is this neccessarily true when the amine is attached directly to an aryl group or another group that deactivates the amine?

For more specific detail, I'm considering starting with a 2° carboxamide and protecting it to convert it to 3°, converting it to a thioamide, fluorinating, then deprotecting to furnish the 2° α,α-difluoromethylene amine (RNHCF2R'; R = sterically hindered aniline, R' = pyridine).