Carvone derivatives

In the same CMS-Xa study [52], a series of (/f)-carvone derivatives, all in their single most stable conformation, were examined with a view to determining the influence of chemical substitution on the PECD. Both the... 

In 1998, Yang and coworkers reported a series of (7 )-carvone derived ketones (63) containing a quaternary center at and various substituents at (Fig. 22) [119]. The ees of fran -stilbene oxide varied with different para and meta substituents when 63b was used as the catalyst. The major contribution for the observed ee difference is from the n-n electronic repulsion between the Cl atom of the catalyst and the phenyl group of the substrate. The substitution at also influences the epoxidation transition state via an electrostatic interaction between the polarized C -X bond and the phenyl ring on franx-stilbene (Table 6, entries 3-7, 10-14). In 2000, Solladie-Cavallo and coworkers reported a series of fluorinated carbocyclic ketones... 

Prins-pinacol condensation of a (Z)-a,p-unsaturated aldehdye and an (S)-carvone-derived alkynyl dienyl diol as illustrated below provided the formyl tetrahydroisobenzofuran as a single diastereomer in 84% yield in two steps <03JA6650>. 

Nicolaou s total synthesis of a marine antitumor agent, eleutherobin [22] (Scheme 12.24), involves the attachment of D-arabinose to the aglycon intermediate. Thus, the glycosidation of the (-F )-carvone-derived hydroxy aldehyde 210 and the trichloroacetimidate 211, derived from... 

Composition h The major components, also mainly responsible for the typical taste and odor, are (+)- car-vone (50-60%) and (+)-limonene (see p-mentha-dienes) (30-45%) the two components together constitute ca. 95% of the oil. Minor components include carvone derivatives such as 1,6-dihydrocarvone (see p-menthenones). 

The group of Lindel realised a novel enantioselective total synthesis of (-l-)-cubitene, during which they formed its challenging 12-membered ring using Smia to mediate the intramolecular coupling of the allyl phosphate and enone in carvone derivative 13 (Scheme 5). ... 

Carvone-derived 2,3-epoxy alcohol derivatives (317) have been found to rearrange with stereoselective formation of ring-contracted ketones (318) in a process where the stereochemical result seems to be independent of epoxide configuration. On the basis of this study, the authors concluded that the rearrangement of tetrasubstituted cyclic epoxy alcohol derivatives remains a transformation for which both regiose-lectivity and stereochemical outcome are difficult to predict. New solid acid catalysts based on silica-supported zinc triflate have been prepared for use in the rearrangement of a-pinene oxide to campholenic aldehyde. ... 

The synthesis of eleutherobin, which has antitumor activity and cytotoxic properties similar to those of taxol, has also been reported (Scheme 41) [181, 182], The carvone-derived acceptor was stereoselectively glycosylated with the arabinosyl trichloroacetimidate (a P = 8 1). The resulting glycoside intermediate was treated as for sarcodictyins A and B to yield eleutherobin and eleuthosides A and B. 

A second method makes use of the lactone (31) from acetone dicarboxylate (40) and for which a synthesis from (—)-carvone has been reported (41). Displacement of chlorine from the 6-aminopenici11anic acid (6-APA) derived P-lactam (32) by (33) illustrates yet another approach to the dia2oketone (28) (42). 

Figure 10. The CMS-Xa predictions for cross-section, the anisotropy parameter —P/2), and the chiral parameter in the carbonyl C li photoionization of (R)-carvone (I) and its indicated derivatives.

Results for these CEBEs are presented in Table 1. As can be seen, for the carvone variants I-V the various substitutions have absolutely no effect at the carbonyl C=0 core, and are barely significant at the chiral center that lies between the carbonyl and substituent groups in these molecules. Only upon fluorine substitution at the tail (molecule VI) does the C=0 CEBE shift by one-half of an electronvolt the second F atom substitution adjacent to the C=0 in the difluoro derivative, VII contributes a further 0.6-eV shift. This effect can be rationalized due to the electron-withdrawing power of an F atom. Paradoxically, it is these fluorine-substituted derivatives, VI, VII, that arguably produce b curves most similar to the original carvone conformer, I, yet they are the only ones to produce a perturbation of the ground-state electron density at the C li core. This contributes further evidence to suggest that, at least for the C li... 

A total synthesis of functionalized 8,14-seco steroids with five- and six-membered D rings has been developed (467). The synthesis is based on the transformation of (S)-carvone into a steroidal AB ring moiety with a side chain at C(9), which allows the creation of a nitrile oxide at this position. The nitrile oxides are coupled with cyclic enones or enol derivatives of 1,3-diketones, and reductive cleavage of the obtained cycloadducts give the desired products. The formation of a twelve-membered ring compound has been reported in the cycloaddition of one of the nitrile oxides with cyclopentenone and as the result of an intramolecular ene reaction, followed by retro-aldol reaction. 

Plant growth regulators, 13 21-60, 284 carvone, 13 28 cytokinins, 13 28-30 ft-decanol, 13 30 dikegulac, 13 30 ethylene, 13 30-32 gamma aminobutyric acid, 13 32 gibberehins, 13 32-35 indole 3-butyric acid, 13 35-36 lactic acid, 13 36 natural product derivatives,... 

Further details of the photoaddition of N-nitrosopiperidine to a-pinene have been published.The claim of a-fenchen-6-one oxime formation (Vol. 7, p. 43) has been retracted the product is optically active carvone oxime. The stereochemistry and conformations of amino-oximes derived from a-pinene nitroso-chloride have been examined. ... 

The paper also reports fragmentation by this reaction of the a-alkoxy hydroperoxide 3, derived from ( —)-carvone, as a novel route to the optically active 4. 

Comparison of the volatile constituents of the oils resulted in the conclusion that the concentrations of terpene hydrocarbons (like pinene, limonene) were higher in the distilled oils, while those of the oxygenated derivatives (like thymol, bomeol, carvone, apiole) were higher in SFE products. 

TERPENELESS OIL. An essential oil from which the teqoene components have been removed by extraction and fractionation, either alone or in combination. The optical activity of the oil is thus reduced. The terpene-less grades are much more highly concentrated than the original oil (15—30 times). Removal of terpenes is necessary to inhibit spoilage, particularly of oils derived from citrus sources. O11 atmospheric oxidation the specific terpenes form compounds that impair the value of the oil for example, d-limonene oxidazes to carvone and y-terpinene to p-cymene. Terpeneless grades of citrus oils are commercially available. 

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