NCPS noncross-linked polystyrene

Scheme 21.13 Synthesis of prostaglandin using isolation tags (Janda et a .). NCPS noncross-linked polystyrene.

Although a large variety of reactions were successfully transferred to the solid phase there are only a few examples of free radical reactions on solid phase [173,174]. The free allyl radical transfer was achieved when the carbohydrate auxiliary was linked to a noncross-linked polystyrene polymer (NCPS) [175]. The use of NCPS instead of cross-linked supports has several advantages, including complete solubility in many organic solvents [176]. The polymer 269 was obtained in a radical polymerization of two equivalents of styrene and one equivalent /7-chloromethylstyrene. The protected D-xylose 270 was covalently linked to the support by a Williamson synthesis generating compound 271 (Scheme 10.88). 

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