Synthesis of a substituted 6,8-dioxabicyclo[3.2.1]octane

Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 692–693, May, 1991.     

Cationic polymerization of 6,8-dioxabicyclo-[3.2.1]octane and 3,6,8-trioxabicyclo[3.2.1]octane

6,8-Dioxabicyclooctane (DBO) and 3,6,8-trioxabicyclooctane (TBO) underwent ring-opening polymerization when treated with PF₅ in dichloromethane at ?78°C. These conditions were outstandingly effective for the polymerization of these bicyclic monomers, as shown by systematic variation of catalyst, solvent, and temperature. Best results were 68–84% yields of poly-DBO, η_inh 0.26–0.33 dl/g, and ～100% yield of poly-TBO, η_inh 0.56–0.80 dl/g. The relationship of these results to those of previous investigators of DBO discussed.     

A facile synthesis of a polyhydroxylated 2-azabicyclo[3.2.1]octane

Synthetic or natural aza-sugars have shown promise as a therapeutic approach to a variety of disease states by acting as transition state mimics to sugar processing enzymes. Although the synthesis of functionalized bicyclo[3.2.1]octanes has been reported, the procedures are relatively long and low yielding. Herein, we report the facile synthesis of polyhydroxylated 2-azabicyclo[3.2.1]octane that can be selectively functionalized.     

Natural polyene pyrones. Synthesis of the 2,6-dioxabicyclo[3.2.1]octane unit of citreoviridinol

The 2,6-dioxabicyclo[3.2.1]octane unit, $\text{viz}$ 10, present in citreoviridinol (1) has been produced in a stereoselective manner by treatment of the epoxide (8) derived from citreoviral (6), $\text{via}$ (7), with $\text{p}$-toluenesulphonic acid.     

A Facile Syntheses of 6-Bicyclo[3.2.1]octanones

Copper oxide-catalyzed decomposition of 1-diazoacetyl-1-methyl-3-methylenecyclohexanes produces strained tricycles whose reduction or hydrolysis affords 6-bicyclo[3.2.1]octanones.     

Synthesis of highly functionalised enantiopure bicyclo[3.2.1]- octane systems from carvone

The commercially available monoterpene carvone has been efficiently converted into the tricyclo[3.2.1.0(2.7)]octane and bicyclo[3.2.1]octane systems characteristic of some biologically active compounds. The sequence used for this transformation involves as key features an intramolecular Diels-Alder reaction of a 5-vinyl-1,3-cyclohexadiene and a cyclopropane ring opening.     

A new route to (+)-estrone using a bicyclo[3.2.1]octane chiral building block

A new route to (+)-estrone has been developed starting from the chiral building block having a bicyclo[3.2.1]octane framework based on the inherent stereochemical chemical nature of the chiral building block.     

Synthesis of 1, 2-diazabicyclo [2.2.2] octane, 1, 2-diazabicyclo [3.2.1]-octane,and their derivatives

1, 2-Diazabicyclo [2.2.2] octane, its 6-methyl homolog, and 1, 2-diazabicyclo [3.2.1] octane are synthesized by a general method involving nitrosation of piperidine carboxylic acids, subsequent reduction to 1-aminopiperidine carboxylic acids, cyclization to 3-keto-1, 2-diazabicycloalkanes, reduction of the latter to 1, 2-diazabicycloalkanes. A number of 2-substituted 1, 2-diazabicyclo [2.2.2] octanes are synthesized.     

Carbon-13 n.m.r. of the 8-phosphabicyclo[3.2.1]octane system

¹³C Chemical shifts and ¹³C? ³¹P nuclear spin coupling constants have been determined for 26 8-phosphabicyclo[3.2.1]octane derivatives, namely phosphines, phosphine oxides, phosphine sulphides and one phosphonium salt. The influence of the phosphorus configuration on δ and ²J(PC) values was examined and other factors influencing the ²J(PC) coupling constant are discussed.     

A Stereospecific Route to 6-Substituted-7-Azabicyclo[3.2.1]Oct-2-Ones

N-carbethoxy-3-exo- or 3-endo-substituted-2-azabicyclo-[2.2.2]oct-5-enes 1 provide the title compounds 2 by a stercospecific route involving bromohydrin formation, reductive dehalogenation and oxidation.     

Rearrangement of a mesylate tropane intermediate in nucleophilic substitution reactions. Synthesis of aza-bicyclo[3.2.1]octane and aza-bicyclo[3.2.2]nonane ethers,imides, and amines

Nucleophilic substitution of 2beta-mesyloxymethyl-N-methyl-3beta-p-tolyl-tropane intermediate with alkoxides, metal imides, or amines was found to lead not only to the expected bicyclo[3.2.1]octane (tropane) ether, imide, and amine derivatives but also to unexpected bicyclo[3.2.2]nonane derivatives. When alkoxides were used as nucleophile, only the rearranged bicyclo[3.2.2]nonane structure was obtained, whereas the use of amines or imides as nucleophile afforded a mixture of the two structures. The bicyclo[3.2.2]nonane structure was assigned by NMR analysis.     

Carbon-13 chemical shifts of bicyclo[3.2.1]octane and bicyclo[2.2.1]heptane derivatives

¹³C chemical shifts of more than fifty bicyclo[3.2.1]octane and bicyclo[2.2.1]heptane derivatives (hydrocarbons, alcohols, ketones and esters) have been determined. The usefulness of ethyl derivatives for the assignment of close ¹³C chemical shifts in bicyclic methyl derivatives is shown both for the bicyclo[3.2.1]octane and bicyclo[2.2.1]heptane series. Comparison of substituent effects on α-, β-, γ- and δ-carbons in both series of compounds shows remarkable differences in steric interactions. In contrast to the rigid bicyclo[2.2.1]heptane system, both chair and boat conformations can be predominant in the bicyclo[3.2.1]octane series with the conformationally flexible 6-membered ring.