A-10-Octalin

10- and Al 9-Octalin. Caution This preparation should be performed in a hood to avoid exposure to amine vapors. Naphthalene (25.6 g. or 0.20 mole, Note 1) is dissolved in a 

Purification of b il0-Octalin. A 1-1. three-necked flask is equipped with a magnetic stirrer, a pressure-equalizing dropping funnel, and a reflux condenser fitted with a nitrogen inlet tube to maintain a nitrogen atmosphere in the reaction vessel throughout the portions of this preparation where anhydrous conditions arc employed. A solution of 2.35 g. (0.062 mole) of sodium borohydrido and I 1.55 g. (0.164 mole) of 2-methyl-2-butene (Note 10) iu 100 ml. of anhydrous t.otrahydrofuran is 

Naphthalene purchased from Eastman Organic Chemicals was used without purification. 

The ethylamine (b.p. 16.6°) and dimethylamine (b.p. 7.4°) may be distilled into the reaction flask from cylinders. The checkers employed amines purchased from Eastman Organic 

Chemicals in sealed ampules. After the ampules had been cooled to 0° in an ice bath, they were opened and the contents were added to flasks cooled in ice baths. Small portions (0.5-1.0g.) of sodium metal were added to each of the cold amines, and then the cooling baths were removed and the amines allowed to distill from the sodium into the reaction flask. 

---

In judging hindrance, it is useful to view the molecule in its three-dimensional, folded configuration. For instance, 17 can be reduced without undue difficulty, whereas 18 requires extreme conditions (Raney Ni, 2(WC, 200 atm) (7), a difference not expected from planar representations of the molecule. Saturation of A -octalin (17) may largely go through a prior isomerization to A -octa in, despite an unfavorable equilibrium 121). 

Direct calorimetric measurements of two ozonides have been reported. Both the enthalpy of combustion of the ozonides and the direct enthalpies of ozonation of the precursor olefin were measured. The first species to be studied was the purported ozonide of A °octalin (l,2,3,4,5,6,7,8-octahydronaphthalene) . It is doubtful that the product of the octalin ozonation reaction would be the molozonide formed by direct addition with no subsequent rearrangement (i.e. ll,12,13-trioxabicyclo[4.4.3]tridecane) but perhaps even less likely is the rearranged and hence normal ozonide, the ll,12,13-trioxa[4.4.2.1]paddlane. From the published enthalpy of combustion of —5628 kJmoU, we derive an enthalpy of formation of this species, whatever it is, of —593.7 kJmoU. ... 

Epoxidation of monoterpenic olefins and A -octalins with dimethyloxirane gives the corresponding epoxides in excellent yields. Some A -octalins are oxidized in a much more stereoselective manner than with m-CPBA . ... 

For example, the dicyanomalonyl radical adds more rapidly to A -octalin than to 1-hexene G. J. Gleicher, B. Mahiou and A. J. Aretakis, J. Org. Chem., 1989, 54, 308. 

Extension of this type of reagent" to the use of sodium dichromate in acetic acid was found to furnish the allylic oxidation of 4,4,10-trimethyl-A -octalin into 7-keto-4,4,10-trimethyl-A -octalin (64) in 65% yield (equation 25) this reaction was employed in the total syntheses of ( )-widdrol (65) and ( )-thujopsene (M)." ... 

In the simplest example, Michael addition to the enone (67) of the cyclohexanone enamine and aldol condensation yielded 4-(3-butenyl)-3-oxo-A -octalin (69). Tbe terminal double bond was oxidized to the ketone (70) by PdCli/CuCl/Oz, and subsequent aldol condensation leads to the tricyclic ketone (71 Scheme 21 ... 

Reduction ofarenes. Calcium in a mixed solvent composed of methylamine and cthylenediamine is comparable to lithium and an alkylamine for reduction of aromatic hydrocarbons to monoenes. Thus naphthalene is reduced by this newer system to A -octalin (82%) and A -octalin (18%). The method is more efficient than one using calcium and liquid ammonia, although the latter method is considerably improved in rate and selectivity by small amounts of HMPT. 

Hydroeyamation (2, 427). Application of the Nagata procedure to the ketone (I) yielded 7-cyano-A -octalin-2-one (2) in 48% yield. No adduct was obtained using classical procedures. 

The stereoselectivity of the ionic hydrogenation reaction appears to be controlled by the steric size of the trialkylsilane in the reduction of A ° -octalin (109 equation 46), which shows a high degree of sensitivity to the steric size of the organosilane hydride donor. ° However, in the reduction of (112 equation 47) there is a considerably smaller change in the range of stereoselectivity of the reduction process. The lower sensitivity in the stereoselectivity of reduction of (112) relative to (109) has been interpreted... 

Solutions of Group I metals in the lower molecular weight amines are more potent reductants than those in liquid ammonia, and as a general rule substrates are more extensively reduced than by the Birch method. o Naphthalene (49 Scheme 48), for example, is reduced by a solution of lithium in ethylamine to a 1 1 mixture of A W- and A -octalins (214) and (215). If ethylenediamine is employed as the medium, the completely saturated decahydronaphthalene is formed, while the proportion of (215) may be increased to 80% by utilizing a (1 1) mixture of ethylamine with dimethylamine. The formation of the more-substituted alkene appears to be a general result for such primary and secondary amine mixtures and has been used to good effect in the reduction of both toluene and cumene to their 3,4,5,6-tetrahydro derivatives (216) and (217), respectively, in ca. 80% yields. A comprehensive review of these kinds of reducing systems, which also draws comparisons with the Birch method, is available,but more recent-... 

The synthesis of ( )-D-homotestosterone and ( )-progesterone has been accomplished via a now classical procedure involving the use of an isoxazole as an annelating agent (67JA5464). The enolate (424), prepared from 10-methyl-A -octalin-2,5-dione, was alkylated by the 4-chloromethylisoxazole (425). The octalindione (426) was treated sequentially with one equivalent of sodium borohydride, hydrogenated, hydrogenolyzed and refluxed with sodium methoxide and then with sodium hydroxide to afford the crystalline enone (427). 

An allylic alcohol unit can also be used to initiate the carbocyclization this vuriulion can he used for the synthesis of A -octalins and A4-hydrindenes.3... 

Use of a co-amine is embodied in an improved procedure for the preparation of A -octalin. A mixture of 0.2 mole of naphthalene and 250 ml. each of ethylamine and dimethylamine is placed in a flask fitted with a dry ice condenser, 1.65 g.-atoms of lithium wire cut in half-centimeter pieces is added all at once, and the mixture is stirred magnetically for 14 hrs. The solvent mixture is allowed to evaporate and the grayish white residue (containing excess lithium) is decomposed by cautious addition of about 100 ml. of water with cooling. The precipitated product is collected and the filtrate extracted with ether distillation affords 19-20 g. of hydrocarbon found by VPC analysis to contEiin 80% of A "-octalin and 20% of A -octalin. Isolation of the major product in pure form is accomplished by reaction of the mixture with bis-3-methyl-2-butylborane, which adds selectively to the less hindered A -isomer. Oxidation of the product with hydrogen peroxide to convert the adduct into an easily separated alcohol, followed by distillation, affords A" " -octalin of 99% purity in yield from naphthalene of 50-54%,... 

In a later paper Meinwald concluded that nitrosyl chloride adds cis to strained double bonds, such as that in norbornene, but that it adds trans to unstrained olefins (A -octalin). In accordance with this view of the addition is a report by Hassner on the reaction of cholesteryl acetate (4). Nitrosyl chloride was passed into methylene chloride or carbon tetrachloride until a deep burgundy color developed, the steroid... 

On exploring the reaction of osmium tetroxide with olefins in a nonaqueous solvent (ether, also benzene, cyclohexane), Criegee promptly confirmed the Boeseken hypothesis. From acenaphthylene, indene, A -ditralin, and A -octalin he obtained nicely crystalline, bright colored osmate esters in yields of 89-99% no... 

---