A-Pinene epoxide

Isomerization of a-pinene epoxide to campholenic aldehyde, an intermediate for perfumery chemicals, has been carried out elegantly with ultra stable Y-zeolite. 

Pinene eo-oxidation with IBA gave selectively a-pinene epoxide and isobutyrie aeid. It is noteworthy that the aetivity of the supported Co-POM catalysts was comparable to the activity of the homogeneous Co-POM, while the epoxide selectivity could increase after the Co-POM immobilization. 

In contrast to a-pinene autoxidation, for which no effect of the support on the reaetion seleetivity was observed, the seleetivity of the eo-oxidation process could be altered by varying the amount of NH2-groups on the support. Thus for Co-POM supported on NH2-MCF and NH2-SBA-I5 (NH2/C0-POM = 30 and 16 mol/mol, respectively), the a-pinene epoxide selectivity attained 94 and 76%, respeetively, at 96% of substrate conversion. 

Campholenic Aldehyde Manufacture. Campholenic aldehyde is readily obtained by the Lewis-acid-catalyzed rearrangement of a-pinene oxide. It has become an important intermediate for the synthesis of a wide range of sandalwood fragrance compounds. Epoxidation of (+)- Ct-pinene (8) also gives the (+)-o -a-pinene epoxide [1686-14-2] (80) and rearrangement with zinc bromide is highly stereospecific and gives (-)-campholenic aldehyde... 

One of the most important aspects of those listed above is catalysis. A great deal of research has been carried out in the investigation of catalysts for the epoxidation of alkenes. The oxidation of a-pinene to a-pinene epoxide (Equation 1) is one of the standard trial reactions for catalyst identification. The Jacobsen manganese complex catalyst, based on a salen derivative, shows brilliant enantioselectivity, whereas the use of related indole derivatives provides greater structural variety and powerful catalysis, but so far shows poorer enantioselectivity (Figure 2). Such catalysts can sometimes be effectively embedded in zeolites. ... 

The ready accessibility of a-pinene epoxide (817) is frequently the reason for its use to make other compounds. A most interesting claim is that with 1 mol% of aluminum isopropoxide at 100-120°C, trans-pinocarveol (603) is obtained, while 5 mol% of the reagent at 140-170°C gives pinocamphone (818). Kane et al. have used the pinanyl oxides cis- and trans-S19 (R = K) to open a-pinene epoxide (817). These alkoxides are made from dimethylsulfmylpotassium and dy-pinanol (819, R = H) (the product of autoxidation of pinane cis here means from ci5-pinane, therefore with the rranj-hydroxyl group) and are among the... 

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