Synthetic applications of fluorous solid-phase extraction (F-SPE)

Abstract

1.1. Synthesis is reaction and separation The enterprise of organic synthesis is a collective endeavor involving reaction and separation followed by identification and analysis.1 The “reaction and separation stage” produces a new organic molecule while the “identification and analysis stage” proves what the molecule is and how pure it is. The yield of every organic reaction depends on both the efficiency of the underlying reaction and the ability to recover the target product in pure form from the reaction mixture. Reaction methods have evolved and improved dramatically over the past decades and continue to do so. On the other hand, while they continued to be refined, the core separation methods that synthetic chemists routinely use have not change for a decade or more. The concept of the “ideal reaction” serves as an inspiring, if unattainable, goal for basic research in synthesis.2 In the trenches (the labs), reactions are usually a means to an end (chemical and drug discovery), and chemists tend to spend more time searching, hoping and wishing for the “ideal separation”1a,b. It is rare not every day that a new, generally applicable separation method comes along. The purpose of this Report is to provide an overview of the increasingly popular new separation technique of fluorous solid-phase extraction (F-SPE). Though it is still less than a decade old,3 the technique has matured rapidly and is now ready for prime time, as illustrated by the expanding uses over the last 2–3 years.4 After a brief introduction of two varieties of F-SPE—standard and reverse—we provide comprehensive tabular collections of published uses in small molecule synthesis that are intended to illustrate both the scope of the method and the diverse array of reagents and materials that are now available. We close by providing interested readers with practical information on how to conduct an F-SPE.