Decalin preparation

The same regioselective and stereospecific reactions are observed in decalin systems. The 3/3-formate 605 is converted into the a-oriented (j-allylpalladium complex 606, and the hydride transfer generates the fra .s-decalin 607, while the cis junction in 610 is generated from the 3tt-formate 608 by attack of the hydride from the /3-side (609). An active catalyst for the reaction is prepared by mixing Pd(OAc)2 and BU3P in a 1 I ratio with this catalyst the reaction proceeds at room temperature. The reaction proceeded in boiling dioxane when a catalyst prepared from Pd(OAc)2 and BujP in a 1 4 ratio was used[390]. 

Phenoxazine analogues 270 were prepared by thermolysis of azides 269 in decalin in 43-72% yields (Scheme 175) (96UP1). 

The vinyl ether is quite stable and can be converted readily to a variety of disubsti-tuted trans-Decalins. Its preparation and conversion to a derivative are given in the procedures. 

Method A i01 Equivalent amounts of a 1,2,3-benzothiadiazole. sulfur (as S8) and DABCO were added to Decalin (10 mL per gram of benzothiadiazole) and N2 was passed through the mixture. The mixture was heated at 160-190 C until N2 evolution ceased (20-90 min). It was cooled and the Decalin was removed by Kugelrohr distillation at 50 C/0.5 Torr. The residue was twice triturated with CH2C12 and the extracts were combined and filtered from sulfur. Chromatography (silica gel, 1 % EtzO/hcxanc) gave the product. The preparations were carried out on a scale of 0.25-10.0 g benzothiadiazole. 

When prepared by thermal condensation of the respective alkoxides and carbonates in hydrocarbon media such as decalin, these catalysts yielded living poly-e-capro-lactone. Its living nature was demonstrated by the increase of DPn with conversion and by the validity of the relation... 

Decalin unit 121, an intermediate in the total synthesis of compactin, has been prepared by intramolecular cycloaddition reaction [117] of trienone-carboxylic acid 122 carried out under either thermal conditions or microwave irradiation. The desired cxo-adduct 123 was the major stereoisomer (Equation 2.34). Similar results were observed in the cycloadditions of the corresponding esters. 

Fused bicyclic systems are those in which two rings share two and only two atoms. In such systems there is no new principle. The fusion may be cis or trans, as illustrated by cis- and /ran -decalin. However, when the rings are small enough, the trans configuration is impossible and the junction must be cis. The smallest trans junction that has been prepared when one ring is four-membered is a four-five... 

However the employment of AI2O3 and Al(OH)0 as a support afforded the dissimilar results as shown in Figs. 1 (b) and (c), respectively. Active carbon does not repel decalin while boehmite and alumina repel extensively decalin, indicating that the affinity between the liquid substrate and the support should be considered in the preparation of the catalysts. 

Scheme 8.15. Preparation of optically active polysubstituted decalines by a lipase-catalyzed domino esterification/Diels-Alder reaction.

Intramolecular Diels-Alder cyclizations of (E)- -nitro-1,7.9-decatrienes under thermal conditions and Lewis acid conditions lead to the formation of decalin ring systems with excellent endo selectivity (Eq. 8.21). This strategy is used for preparing of the AB ring system of norzoanthamine.33... 

The 1,2-carbonyl transposition takes place through the enJo-epoxide 18 easily prepared through the tosylhydrazone 16, followed by regioselective cleavage to the less substituted double bond (17) with 2 equivalents of methyllithium [4] and epoxidation with MCPBA in chloroform from the more accesible convex face of the decalin system. 

Uses Intermediate for phthalic anhydride, naphthol, 1,4-naphthoquinone, 1,4-dihydro-naphthalene, 1,2,3,4-tetrahydronaphthalene (tetralin), decahydronaphthalene (decalin), 1-nitro-naphthalene, halogenated naphthalenes, naphthol derivatives, dyes, explosives mothballs manufacturing preparation of pesticides, fungicides, detergents and wetting agents, synthetic resins, celluloids, and lubricants synthetic tanning preservative emulsion breakers scintillation counters smokeless powders. 

Isomeric l,3a,4,6a- (220) and l,3a,6,6a- (91) dibenzotetraazapentalenes can be prepared from the thermal decomposition of 2-((9-azidophenyl)-2//-benzotriazole (224) and - o-azidophenyl)-2//-benzotriazole (230), respectively, in high boiling solvents such as 0-dichlorobenzene and decalin. This synthesis was improved upon when it was found that (220) and (91) can be prepared from the reactions of 2-((9-nitrophenyl)-2//-benzotriazole (226) and l-(o-nitrophenyl)-2//-benzotriazole (229), respectively, with triethyl phosphite in refluxing xylene. ... 

Since the first report in 1973, there has been significant growth in the use of rhodium catalysis to cleave strained ethers and amines, particularly in the preparation of enan-tiomericaUy enriched decalins, cyclohexenes, amino alcohols, and diamino compounds. This chapter describes the major advances in synthetic capabihties and outlines the mechanistic evidence pointing to a working model for the reaction pathway in these processes. 

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