Scavenging of fluorinated N,N'-dialkylureas by hydrogen binding: a novel separation method for fluorous synthesis.

[reaction: see text] A dramatic solubility increase in fluorous solvents is observed for N,N'-di(polyfluoroalkyl)ureas when hydrogen binding complexes are formed with commercially available perfluoroalkanoic acid scavengers. As a case example, analytically pure peptides and esters are obtained using this novel separation method.