Polymer supported reagents in synthesis

Jamieson C, Congreave MS, Emiabata-Smith DF, Ley SV (2000) A rapid approach for the optimisation of polymer supported reagents in synthesis. Synlett 603-607... 

Ley SV, Baxendale IR (2002b) New tools and concepts for modern organic synthesis. Nat Rev Drug Disc 1 573-586 Ley S V, Massi A (2000) J Comb Chem Polymer supported reagents in synthesis preparation of bicyclo[2.2.2]octane derivatives via tandem michael addition reactions and subsequent combinatorial decoration. 2 104—107 Ley SV, Schucht O, Thomas AW, Murray PJ (1999) Synthesis of the alkaloids ( )-oxomaritidine and ( )-epimaritidine using an orchestrated multi-step sequence of polymer supported reagents. J Chem Soc Perkin Trans 1 1251— 1252... 

Ley, S.V. and Massi, A. (2(XX)) Polymer supported reagents in synthesis preparation of bicyclo[2.2.2]octane derivatives via tandem Michael addition reactions and subsequent combinatorial decoration. J. Comb. Chem. 2 104-107. 

Polymer-Supported Reagents in Organic Synthesis, eds. P, Hodge and D. C. Sherrington, Wiley, Chichester, 1980, p. 28. 

Fig. 7.7 Principle of polymer-supported reagents in organic synthesis.

The use of polymer-supported reagents in combinatorial chemistry has received much attention in recent years, and a polymer-supported acylating reagent (supported on a ROMPGEL) has been used for the synthesis of 1,2,4-oxadiazoles in solution, (see Equation 37), <2000CCHT131>. 

Parlow, J. J. Mischke, D. A. Woodard, S. S. Utility of Complementary Molecular Reactivity and Molecular Recognition (CMR/R) Technology and Polymer-Supported Reagents in the Solution-Phase Synthesis of Heterocyclic Carboxamides, /. Org. Chem. 1997,62, 5908. 

Scheme 1, Polymer-supported reagents in clean synthesis 2.1. The evolution of supported reagents - The perruthenates...

Polymer-supported enzymes have been combined with polymer-supported reagents in the synthesis of the bryostatins. The nitrone derived from the nitro compound 43 supported on a soluble aryl poly-ether polymer undergoes an efficient 1,3-dipolar cycloaddition with butenone to give the isoxazoline 44 and hence by reduction the racemic syn compound 45 required for the synthesis.16... 

This chapter deals with both initial developments as well as more recent advances in the area of polymer-supported nucleophilic and electrophilic reagents, and reagents intended for radical-mediated reactions. Reviews by Kirschning [1] and Ley [2] cover this area up to 2001, and we also refer to the Ley group for reports on the application of polymer-supported reagents in total synthesis [3-5]. More details can also be found in reviews by Bradley [6] and Drewry [7]. 

JJ Parlow, DA Mischke, SS Woodard. Utility of complementary molecular reactivity and molecular recognition (CMR/R) technology and polymer-supported reagents in the solution-phase synthesis of heterocyclic carboxamides. J Org Chem 62 5908-5919, 1997. 

The use of polymer-supported reagents in organic synthesis effectively reduces workup and purification to a simple filtration. Polymer-supported reagents can also be used in conjunction with the microwave heating, that has... 

Ploypradith, P., Kagan, R.K., and Ruchirawat, S. (2005) Utility of polymer-supported reagents in the total synthesis of lamellarins. J. Org. Chem., 70, 5119-5125. 

Under certain condition, however, reactions are still preferably conducted in solution. This is the case e.g., for heterogeneous reactions and for conversions, which deliver complex product mixtures. In the latter case, further conversion of this mixture on the solid support is not desirable. In these instances, the combination of solution chemistry with polymer-assisted conversions can be an advantageous solution. Polymer-assisted synthesis in solution employs the polymer matrix either as a scavenger or for polymeric reagents. In both cases the virtues of solution phase and solid supported chemistry are ideally combined allowing for the preparation of pure products by filtration of the reactive resin. If several reactive polymers are used sequentially, multi-step syntheses can be conducted in a polymer-supported manner in solution as well. As a further advantage, many reactive polymers can be recycled for multiple use. 

From a medicinal chemist s point of view, oxadiazoles are among the most important heterocycles as they are one of the most commonly used bioisosters for amide and ester groups [67]. As such it is hardly surprising that the two regioisomeric oxadiazole scaffolds received the most interest in the field of microwave-assisted synthesis using polymer-supported reagents. 

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