Microwave-Enhanced Fluorous Chemistry

The combination of microwave heating and fluorous chemistry is of considerable interest, as this approach combines fast chemistry and easy separation. 

This area has been reviewed recently and only some of the latest papers will be discussed here. 

Microwave-assisted fluorous Ugi reactions were presented where the reaction times and convenient separation techniques appeared more attractive than the corresponding room temperature methods with traditional scavenging techniques.  

A parallel synthesis method for the synthesis of a dihydropteridine library in five steps was recently published by Zhang. The synthetic route was based on the use of fluorous amino acids, which were prepared from A-Boc-amino acids. The final cyclization was promoted by the use of microwave heating. 

---

Abstract Current microwave-assisted protocols for reaction on solid-phase and soluble supports are critically reviewed. The compatibility of commercially available polymer supports with the relatively harsh conditions of microwave heating and the possibilities for reaction monitoring are discussed. Instrmnentation available for microwave-assisted solid-phase chemistry is presented. This review also summarizes the recent applications of controlled microwave heating to sohd-phase and SPOT-chemistry, as well as to synthesis on soluble polymers, fluorous phases and functional ionic liquid supports. The presented examples indicate that the combination of microwave dielectric heating with solid- or soluble-polymer supported chemistry techniques provides significant enhancements both at the level of reaction rate and ease of purification compared to conventional procedures. 

---