Decalin, product yields from

A recent study has provided the needed information [108]. Product yields from the Si state of cis- and trans- decalins were determined in 7.6 eV photolysis. Only 40-50% of these states were found to fragment (which is an unusually low dissociation yield for a saturated hydrocarbon). The yields of the solvent Si states in 3 MeV 3-radiolysis were determined and, combined with the photolysis results, were used to estimate the fraction of radiolytic products that originate from the Si states. The rest of the products were assigned to the Ti states. Table 1 summarizes the results. As seen from this table, for cis- and trans-decalins the probabilities fs of singlet recombination are close to 0.5. This probability is in fair agreement with the recently corrected estimate of f ... 

Thermal rearrangement of 2-vinylaziridine 203, with an electron-withdrawing substituent on the nitrogen atom, at reflux in decalin predominantly yielded 2-pyr-roline 204 along with some 3-pyrroline derivatives 205 (Scheme 2.50) [79]. A similar reaction was also observed with l-alkyl-2-phenyl-3-vinylaziridines 206 [80]. From these observations, the nature of the products formed depends on the natures of the substituents on the aziridine ring if the ring carbon carries a phenyl substituent, the thermolysis in most cases preferentially yields 2-pyrrolines. 

Alcohol dehydrogenase from pig liver (/ e-face selective), from Mucor javanicus (Si-face selective), and, especially, from horse liver (/fe-face selective) can be used for the reduction of cyclic ketones. The horse liver enzyme is very well characterized and models for the prediction of the stereochemical course of the reaction have been developed278,279. When subjected to horse liver alcohol dehydrogenase (HLADH) reduction, the following decalin derivatives yield products with >98% ee279,280. e.g. ... 

The presence of an additional stereocenter in the ether linkage of PhCHO-derived trienes provides the possibility for additional stereocontrol. Thus thermolysis of triene 44 afforded a 2 1 mixture of decalin products 45 and 46 in excellent yield. These ari.se respectively from endo and exo addition of the diene to the same diastereoface of the dienophile via a T. S. in which the phenyl substituent in the tether is pseudo-equatorially disposed (Scheme 10-16). 

On the other hand, in the oxidation of frans-cyclohexane-based substrates, oxidation at methylenic positions was found to be in competition with that of tertiary C-H bonds. fra s-l,2-DMCH yielded a normalized 24 76 3°/2° ratio, and this trend was even more significant in the oxidation of frans-decaline (4 96), indicating that products arising from methylene oxidation are largely dominant. The rationale for this behavior lies on the steric demand exerted by the methyl group in the a-position of the pyridine, which remains in close proximity to the iron site. This fact favors preferential oxidation at the spatially more accessible methylenic sites in contrast to the more embedded tertiary C-H bonds. More importantly, this could be applied to divert regioselectivity in the C-H oxidation of (-F)-neomenthyl esters (Scheme 29). Whereas [Fe(OTf)2(pdp)j offered poor discrimination between secondary and tertiary C-H bonds, [Fe(OTf)2((5,5,/ )-mcpp)] and [Fe(OTf)2( Pytacn)] were found to be complementary, the former... 

The Johnson group began by examing the solvolysis of 5-hexenyl nosylate (65) in formic acid. This reaction gave only small amounts of cyclohexanol and cyclohexene, but illustrated that that cyclization was possible. Solvolysis of diene 66 gave cyclohexanol 67 as the major product. This product results from addition of the electrophilic carbon (Ci) and oxygen nucleophile (formate) across the fm r-olefin. Decalins 68-70 were produced in low yields, but it was notable that only fm -fused decalins were produced. This observation was consistent with an addition of electrophilic carbon (Ci) and nucleophilic carbon (Cio) across the af-olefin (see B in Steroids-12). 

Cyclopropyltriphenylphosphonium Bromide (5). The lactone salt is pyrolyzed by placing it in a round-bottom flask fitted with an adaptor attached to a vacuum source (aspirator is sufficient). The flask is heated (oil bath) to 180-190° for 48 hours. The residue is a virtual quantitative yield of the tan product, which may be crystallized from ethyl acetate giving cream crystals, mp 189-190°. An alternate setup is convenient if a drying pistol (Abderhalden) is available. The compound is placed in the pistol, which is then evacuated. Decalin (bp approx. 187°) is refluxed over the pistol to provide the heating source. The work-up is the same. 

In the course of studying the bromination reactions of the bicyclic systems we noticed that the reaction temperature has a dramatic influence on the product distribution. Increasing of the temperature gives non-rearranged reaction products (refs. 1,2). For this reason, we submitted 1 to high temperature bromination. To a solution of 1 in decalin at 150 C was added a hot solution of bromine in decalin in one portion. The colour of bromine disappeared immediately. After silica gel chromatography followed by fractional crystallization we isolated four products 2-6 in yields 8, 35, 37, and 9 % respectively. The structure of these compounds has been elucidated on the basis of spectral data by iH NMR and NMR experiments and by comparison with those reported in the literature. Symmetrical endo-c/5-isomer 6 has been observed for the first time. Studies concerning the mechanism of syn-addition show that the syn-adduct can arise either from direct... 

Smith and Burwell [61) showed that the reaction of deuterium with j9.io-octalin, which is catalyzed by reduced platinum oxide, yields a mixture of cis- and /mws-decalins containing an average of nearly three deuterium atoms per molecule. Under the same conditions J -octalin gave somewhat less of the cis isomer but the saturated products contained an average of two deuterium atoms per molecule. From a detailed analysis of the distribution of deuterium in the products they concluded that most of the cis- and all of the frans-decalin produced from... 

The mechanistic and synthetic groundwork has been unequivocally established for the consecutive cycloreversion transannular ene reaction sequence, from which /ra/w-decalin derivatives with a hydroxyl group at the ring junction are produced.146,147 As an example, the thermally induced cycloreversion of the ester 43 at 200°C affords 45 in an astonishing 96% yield.146 Presumably the initial cycloreversion product 44 is converted by a transannular ene reaction to generate the decalin 45.146 However, not all the cycloreversion reactions proceed to give a single product as predicted, as can be shown by the examples collected in Table 7. In fact, closer inspection of work already reported has shown that complex product mixtures are usually obtained from cyclobutane cycloreversion reactions.143,148 152... 

Cyclotriveratrylene/1180-60-5] (34) is a cyclocondensation product of veratrole with formaldehyde. It possesses a stable trigonal crown conformation and forms crystalline inclusion compounds with benzene, chlorobenzene, toluene, thiophene, decalin, chloroform, acetone, carbon disulfide, acetic acid, and butyric acid (101). Their structures consist of columns of cyclotriveratrylene molecules that are not amenable to close packing and provide channels into which the guests are accommodated. A number of modified host structures, derived from prototype (34) have been prepared. The hexaphenol analogue cyclotricatechylene also yields well-defined channel inclusions (101). They involve mosdy polar guests and the structures are held by hydrogen bonding. 

The minor product 86, obtained in the synthesis of vertaline (61) from 84 (Scheme 9), was treated with diethyl azodicarboxylate and triphenylphosphine in the presence of benzoic acid to give the benzoate 87, with inversion of the configuration at C-2, in 77% yield. Hydrolysis of 87 followed by lactonization under Mukaiyama-Corey or Masamune conditions afforded decaline (62) in 57 or 45% yield, respectively. 

Figure L Yields of products from Tet-ralin and the ratio of trans/cis Decalin as a function of added Western Kentucky, Homestead mine coal...

Transesterification of the /erf-butyl ester 29.1 to the corresponding methyl ester 29 2 [Scheme 6.29] is not straightforward. Typical acid-catalysed cleavage of the tm-butyl ester is precluded by the acid-sensitivity of the fiiran. whereas basic methanolysis suffers from the electrophilicity of the unsaturated lactone. However, brief immersion of a thin layer of 29.1 in a round bottom flask in an oil bath pre-heated to 210 °C, followed by treatment of the crude product with (trimethylsi)y])diazomethane afforded the methyl ester 29.2 in near-quantitative yield.76 The elimination did not proceed in refluxing decalin (190 °C). 

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