Norcamphor oxidation

Whereas exo-norbornene oxide rearranges to nortricyclanol on treatment with strong base through transannular C-H insertion (Scheme 5.11), endo-norbornene oxide 64 gives norcamphor 65 as the major product (Scheme 5.14) [15, 22]. This product arises from 1,2-hydrogen migration very little transannular rearrangement is observed. These two reaction pathways are often found to be in competition with one another, and subtle differences in substrate structure, and even in the base employed, can have a profound influence on product distribution. 

The ( )-tricyclic lactam ester 39, yet another emetine precursor (34), was also prepared by Takano s group (32,33,35) from ( )-norcamphor (74). Baeyer-Villiger oxidation of ( )-74 and subsequent ethylation yielded the ( )-lactone 75, which was then condensed with 3,4-dimethoxyphenethyla-mine and oxidized. The resulting ( )-ketone 76 was cleaved through the ( )-thioketal 77 to afford the ( )-amido acid 78. Exposure of ( )-78 to Mel... 

RuOj. They found carbon tetrachloride and chloroform to be the only satisfactory common solvents, and most workers have used carbon tetrachloride. Corey et a/. used Freon 11 (CCI3F, b.p. 22°) for oxidation of norbomeol-d with RUO4 on a microscale to norcamphor-d. 

Thus hydroboration-oxidation of norbornene yields 99.5% exoiV> (10). Similarly, the base-catalyzed deuterium exchange of norcamphor gives an exo endo ratio of 71535 (32). It is now suggested that ionization in such U-shaped structures likewise... 

Another novel approach starts with norcamphor (430), which is converted by Baeyer-Villiger oxidation into the lactone (431, R=H). Stereospecific alkylation of this with sodium hydride and ethyl iodide gives the equatorial ethyl compound (431, R=Et), which is converted into the amide (432) on treatment with homoveratrylamine. Oxidation of this alcoholic amide gives the keto-amide which is converted into the dithioke-... 

Oxidation of isonitroso norcamphor with Pb(CH3COO)4/ CH2CI2... 

The last VCD example by Lattanzi et al. describes the use of VCD and DFT calculations to assign the absolute configuration of a recently prepared (15,4/ )-norcamphor-derived furyl hydroperoxide, (+)-8, introduced as a less hindered and more reactive stereoselective oxidant in organic synthesis. During the preparation of 8 through the hydroperoxidation of an alcohol precursor via nucleophilic substitution, it is expected that epimerization will occur at carbon 2 of the bicyclic framework leading to the formation of either exo- or endo-8 (Figure 53.25). Therefore, the... 

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