S-Pinene

There are four distinct terpenes known under this name, namely, a-pinene, /S-pinene, 8-pinene, and isopinene. It must be emphasised, however, that they are all of different constitution, and the customary nomenclature is ill-chosen, as they should be known by entirely different names. 

Pinene in one form or another has been described under numerous names, such as terebenthene, australene, eucalyptene, laurene, olibene, and massoyene, all of which are more or less impure forms of a-pinene or /S-pinene. 

CIS of potassium permanganate in 2000 c.c. of water is placed in a, and an emulsion of 100 grams of the hydrocarbon in 600 c.c. of water is gradually added in small portions. The mixture is kept cool by means of a current of cold water, and shaken continuously. The oxidation products are then treated as follows The liquid is filtered from manganese oxide, and evaporated to about 1000 c.c., saturated with carbon dioxide, and the neutral and unaltered compounds removed ly extract jn with ether in the usual manner. The crude pinonic acid is separated from its potassium salt by sulphuric acid and is then extracted with ether. If /S-pinene be present, nopinic acid will be present... 

Kennedy, J. P. and Chou, T. Poly (iso butylene-eo-(S-Pinene) A New Sulfur Vulcanizable,... 

Study of the photochemistry of myrcene, 23, a triene containing both a conjugated diene system and a remote, unconjugated double bond, has been exceptionally informative. Direct excitation produces a cyclobutene derivative 24, /S-pinene, and a host of minor products287 including 25. In contrast, indirect excitation using a number of sensitizers gives only a derivative of bicyclo[2.1.1]hexane, 25.288... 

Pinocarveol has been prepared by the autoxidation of a-pinene,5 by the oxidation of /S-pinene with lead tetraacetate,6 and by isomerization of a-pinene oxide with diisobutylalumi-num,7 lithium aluminum hydride,8 activated alumina,9 potassium ferf-butoxide in dimethylsulfoxide,10 and lithium diethylamide.11 The present method is preferred for the preparation of pinocarveol, since the others give mixtures of products. It also illustrates a general method for converting 1-methylcy-cloalkene oxides into the corresponding exocyclic methylene alcohols.11 The reaction is easy to perform, and the yields are generally high. 

The name pinanyl is recommended for the univalent saturated radical (CjqH ij-j derived from pinane because in the terpene literature the name pinyl (which would be the name formed by replacing the ending ane of pinane by yt) has been used exclusively and frequently for a 10 15—radical (with point of attachment at position 3) derived from /S-pinene. Since pinanyl must be an exception to the general rules, the names of the other two saturated radicals in the pinane-group series, that is, pinanylidene and pinanylene, should also be exceptions for consistency. In the series of nor- names, however, it does not seem necessary to insert the "an syllable because the radical names norpinyl and the like have not been used in the literature. 

A rhodium-catalyzed hydroformylation was also carried out with the bicyclic terpenes [S-pinene and camphene [44, 45]. The influence of phosphine and phosphite ligands (L) on the formation of the different product isomers of the hydroformylation of [S-pinene was studied by adding different mono- and bidentate ligands. However, the basicity of the ligands proved to be relevant for favoring the c/.v-isomer. A steric influence of the ligands to favor one isomer was not found (Scheme 14). 

Roberts and Day (172) investigated the polymerization of a- and /S-pinenes with Friedel-Crafts halides as catalysts in toluene at 40—45° C. Under comparable conditions the / isomer polymerized much more vigorously than the a, and it gave higher conversions and higher softening products. 

Roberts and Day (172) postulate that solid polymer formation from a-pinene occurs via isomerization to limonene which then yields the polymer. However, the expected polylimonene does not explain the fact that considerably more than one double bond per monomer consumed disappears during polymerization. Thus it was postulated (172) that double bonds in different molecules mutually react and consume each other by crosslinking. Apparently, the expected (analogous to poly-/S-pinene) polymer does not form from a-pinene. 

Steric differences also explain the preferential binding of silver at the exocycUc alkene of limonene (49) . The binuclear reagents are effective at shifting the spectra of other terpenes with either an exocycUc double bond, such as S-pinene (50) and camphene (51), or an endocyclic double bond, such as a-pinene (52) and A-3-carene (53) . ... 

A 1968 estimate of the cost breakdown for a plant with a colunm 4 ft dia by 15 ft high and a throughput of 200-920 tons/yr has been converted to a percentage basis in Table 15.7 because of its age. The costs are said to not vary greatly with throughput or the nature of the separation, although this analysis has been made specifically for the separation of a- and )S-pinenes. The temperature was 165°C and the solvent was Carbowax 20M. The design was based on data in a 4in. dia column which had a capacity of 200-1500 mL/hr. 

The reactions of nitrones with indoles have been applied to the formation of several A/ -hydroxylamines and symmetrical and unsymmetrical diindolylalkanes. Chiral auxiliaries, alcohols derived from (lS)-(—)-)S-pinene (R OH), lead to an enantio-selective synthesis when R acetoacetate reacts with 3-(2-hydroxyethyl)indole in the presence of, for example, Bp3.Et20, forming (27). Methyl migration follows Friedel-Crafts reaction of ( 113)3 SiCCb benzene in the present of AICI3 and (28) is formed. ... 

Representative Chemicals Turpentine is primarily composed of CioHig terpene hydrocarbons such as a-pinene, S-pinene, limonene, 3-carene, and camphene. It may also contain other acyclic, monocyclic, or bicyclic terpenes, oxygenated ter-penes, and anethole... 

Bicyclo[3,l,l]heptanes.—Some i.r. and Raman spectral bands have been assigned for a- and /S-pinene and the Raman circular intensity differential spectrum has been recorded for (-)-ct-pinene. ° ... 

Hydroformylation of (—)- -pinene with hydrogen-carbon monoxide in the presence of cyclo-octa-l,5-dienylrhodium chloride favours the formation of (216 X = CHO), which is readily obtained optically pure via the (-)-tripinyltrioxan with (8-pinene, the preferred product is 10-formyl-c/s-pinane. ° /S-Pinene is converted into the azide (213 X = N3) using Tl(OAc)3-Me3SiN3 cf. Vol. 4, p. 59)." ... 

Papers of no great novelty concern the attempted synthesis of isopinothiocam-phone [c/5-(210 R = Me, X = S)], lead oxide oxidation of /S-pinene, peroxidation of a-pinene over glass wool, the formation of 2a,3a-epoxypinane and hydration into sobrerol, reduction of chrysanthenone (187), the stereospecific chlorohydroboration-oxidation of /S-pinene to c/s-myrtanol and of a-pinene to (216 X = OH), and the conversion of nopinone into [3- H]myrtenal. ... 

From the range of synthetic applications of Brown s pinene-derived allyl- and crotylborane reagents illustrated in these selected examples, it is clear that they are excellent reagents for the synthesis of chiral homoallylic alcohols from chiral and achiral aldehydes alike. That so many researchers have applied these reagents in their research also attests to the great utility of these reagents in organic synthesis. 

As mentioned above, some arylalkenes, such as stilbene, form complexes with Ag+. Such complexes are also formed between Ag+, as added silver perchlorate, and simpler alkenes. Typical of this is the interaction with 1-methylenecyclohexane when a crystalline complex is formed. Irradiation of this complex in the polycrystalline state or in solution in methanol affords isomerization to 1-methylcyclohexene by a 1,3-hydrogen migration path. Further irradiation brings about the stereospecific formation of the exo,trans,exo-dimer (24) of 1-methylcyclohexene. Less specific photodimerization is also reported for the irradiation of the /S-pinene (25)/silver perchlorate complex69 The mechanism was thought to involve a silver/cyclohexenyl radical similar in type to that observed in the y-radiolysis of silver/cycloalkene complexes70,71. 

Hydroboration of (-f)-verbenone (202 X = 0) and treatment with hydroxyl-amine-O-sulphonic acid results in a 65% yield of (-l-)-cw-S-pinene (213) by elimination, with no resultant amine. Dehydrated neutral alumina may be used for the room-temperature concerted 1,2-elimination from 10-pinanyl tosylate to yield /3-pinene (70%) and some a-pinene (14%) with little rearrangement to camphene/ The addition of diethyl N,7V-dichlorophosphoroamidate to (-)-a-pinene yields (-t-)-(214) and the structure of the adduct (-)-(13) from MePCl2-AICI3 addition to (-)-a-pinene has been confirmed by X-ray analysis. The addition of HCNO to a- and / -pinene was reported earlier. 

Ring expansion of a- and fi-pinene. When either a- or S-pinene, (1) or (2), is heated neat with an initial pressure of 30 psi CO at 160 for 68 hr. with an equimolar amount of iron pentacarbonyl, two ketones, (3) and (4), are obtained, formed by insertion of CO into the cyclobutane ring together with some a-pinene. Both ketones are optically active. The Cotton effects are of nearly the same... 

Ene reactions cyaHobis methylthio)methylation. The reagent undergoes ene reactions with alkenes. The product is readily converted into an anion (LDA or n-butyllithium), which, in the presence of HMPT, undergoes a [2,3]sigmatropic rearrangement the resulting thiolate anion can be alkylated. This allylic cyanobis-(methylthio)alkylation is illustrated for the case of )S-pinene (2). 

Nabilone is a synthetic cannabinoid with a pharmacological profile comparable to dronabinol. It was developed by Eli Lilly to treat vomiting during cancer treatment, and is marketed as the racemate. [144] However, Eli Lilly has also developed syntheses ofthe enantiomericaUy pure product, starting from )S-pinene. [145,146]... 

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