Supported magic-angle spinning

One of the most time-consuming steps in synthesis on solid supports is the adaptation and optimization of reaction conditions. Furthermore, the optimization process is difficult to monitor on the solid support. Magic-angle spinning NMR (MAS) or FT-IR can be used, but these are technically very demanding. A possible solution is the concept of dual linkers involving an analytical unit [200]. These can be employed not only to optimize chemical reactions on a support, but also for quality control of the compound libraries. The basic principle is outlined in Fig. 15. 

Synthesis of compounds on solid-phase supports became quite popular in the late 1990s and, though interest might have waned a little more recently, there may still be a demand for it in some establishments. If monitoring reactions carried out on resins is what is required, then a magic angle spinning (MAS) probe is the only way to go. 

A. Bianco, J. Furrer, D. Limal, G. Guichard, K. Elbayed, J. Raya, M. Piotto and J. P. Briand, Multistep synthesis of 2,5-diketopiperazines on different solid supports monitored by high resolution magic angle spinning NMR spectroscopy,./. Comb. Chem., 2000, 2, 681-690. 

P. Rousselot-Pailley, N. J. Ede and G. Lippens, Monitoring of solid-phase organic synthesis on macroscopic supports by high-resolution magic angle spinning NMR, J. Comb. Chem., 2001, 3, 559-563. 

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