PREPARATION AND APPLICATIONS OF POLYMER-SUPPORTED HALOGENATED BENZOQUINONES AS OXIDATIVE AGENTS

摘要

This invention provides a general method for the synthesis of polymer-supported benzoquinones described by the following generic structure I: wherein: ., X, R<1>, R<2> and R<3> are described in the main text. The general concept of the method consists of the use of a halogenated starting material of the general structure II (Figure 1) which by an nucleophilic substitution reaction (NSR) or a palladium mediated coupling (PMC) is either directly loaded on a resin to afford IIIa (Path A) or transformed to intermediate IIIb (Path B) which is subsequently (with or without modification) loaded on a resin to afford once again IIIa. Deprotection and/or oxidation of IIIa, if needed, afford target solid-supported oxidants I The polymer-supported benzoquinones I are used for the oxidation of hydroquinones to quinones, for the oxidation of benzylic alcohols the aldehydes, for the removal of p-methoxybenzyl and related protective groups, for the dehydrogenation of tetrahydronaphthalene derivatives and for the dehydrogenation of steroid 4-en-3-ones. The polymer-supported reagent after its use is regenerated upon treatment with an oxidative agent.