Preparation of acid-resistant heavy fluorous tags for recycling in synthetic systems

Acid-resistant heavy fluorous tags, in which all three fluorous chains are tethered in a symmetric manner by carbon–carbon linkage, were designed and synthesized from ethyl crotonate. They were designed also to possess a reactive OH group at a central position, not only for conjugation with a target molecule but also for tag recycling. The tag with an alkyl spacer equipped the primary OH group had the greatest reactivity in conjugation reactions with target molecules and could be recovered in the highest yields, implying its potential for use in recycling applications.