Polymer-Supported Alkyl Azodicarboxylates for Mitsunobu Reactions

Article abstract of DOI:10.1021/ja00193a032

Reaction of hydroxymethyl polystyrene 1 (1percent cross-linked) with phosgene followed by methyl carbazate gives methyl hydrazodicarboxylate polystyrene resin 2, which upon oxidation (e.g., N-bromosuccinimide/pyridine or chlorine/water) affords methyl azodicarboxylate polystyrene resin 3.This substitute for soluble dialkyl azodicarboxylates functions well as an easily separable (insoluble) and nonexplosive reagent in Mitsunobu reactions.In the cases examined, yields of hydroxyl replacement by oxygen, nitrogen, and carbon nucleophiles are comparable, product purification isfacilitated, and the polymeric reagent can be reoxidized and reused at least five times without loss of activity.