Hydroperoxides hydrogenolysis

The main goal was to produce CDPG on a large scale. Tetrazole activation was not investigated because acceptable yields were observed when pyridi-um hydrochloride was employed (step a). Cumene hydroperoxide was used as a useful oxidant (step b). To be successful, deprotection by catalytic hydrogenolysis (step c) must proceed in the absence of P species. Otherwise the efficiency of catalytic hydrogenolysis is severely diminished. 

Carbonyl group, nucleophilic addition cychzation, 230, 233, 245-52, 253 Carbonyl hydrate, hydroperoxide hydrogenolysis, 156 Carbonyl oxides... 

With the aim of developing a new, higher effective method of toluene hydrogenolysis, homogeneous hydrogenolysis to benzene with hydroperoxide participation under atmospheric pressure was studied [145, 146]. 

The hydrogenolysis of 0-0 linkages is involved in the hydrogenation of peroxides, hydroperoxides, and ozonides. Decomposition may occur catalytically in the absence of hydrogen, as was observed in as early as 1818 by Thenard with hydrogen peroxide in the presence of platinum. 

The cleavage of the oxygen-oxygen bond in hydroperoxides to give the alcohols takes place over platinum, >180 palladium > 82 anj Raney nickel 3 catalysts at room temperature and atmospheric pressure (Eqn. 20.70). The use of Lindlar s catalyst or a similarly deactivated catalyst is preferred for the cleavage of allyl hydroperoxides in order to minimize the hydrogenolysis of the resulting allyl alcohol (Eqn. 20.71). 2,183... 

This process is a variant of the PO/SM process that uses cumene instead of ethylbenzene and recycles the coproduct cumyl alcohol via dehydration to a-methyl-styrene and hydrogenation back to cumene (the latter two steps can be combined into a single hydrogenolysis step). Cumene hydroperoxidation technology is well-known for its use in phenol and acetone production. 

Figure 1.7 Propylene oxide formation from propylene with cumene hydroperoxide (CHP) as a recyclable oxidizing agent. After hydrogenolysis of the alcohol (which is the reduction product) to cumene, cumene hydroperoxide is generated again through oxidation of the cumene in air. Adapted from Ref. (197a), with permission from the Royal Society of Chemistry.

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