Cyclooctene with acetone

Swenton and co-workers have shown that both 6-azauracil and 6-azathymine photocycloadd with acetone sensitization to olefins to give (2 + 2)-photocycloadducts in high yield and with high regiospecificity69. 6-Azauracil has been shown to cycloadd to ethylene, tetramethylethylene, isobutylene, cyclohexene, cis- and trans-cyclooctene, ethyl vinyl ether, vinyl acetate, and isopropenyl acetate. Cis- and trans-cyclooctene give the same epimeric mixture of cycloadducts in approximately the... 

Cooling with acetone. A soln. of l,5-cyclo6ctadiene in methanol hydrogenated with 5%-Pd-calcium carbonate at 2 atm. until 1 molar equivalent of Hg has been absorbed cfs-cyclooctene. Y 87%.—The heat of reaction is conveniently dissipated by wrapping the bottle with a towel and periodically saturating it with acetone. P. D. Gardner and M. Narayana, J. Org. Chem. 26, 3518 (1961). 

C. trans-Cyclooctene. A 500-ml., three-necked, round-bottomed flask is equipped with a nitrogen inlet capillary tube (Note 9), a short (10-20 cm.) unpacked column (Note 10), and a pressure-equalizing dropping funnel. The round-bottomed flask is connected by the unpacked column to a 100-ml. trap cooled in an ice bath. This trap is then connected to a 200-ml. trap cooled in dry ice-acetone (Note 11). The flask is heated in an oil bath to 110-125°, and the apparatus is evacuated to a pressure of ca. 10 mm. under a constant sweep of nitrogen. The hydroxide solution is added dropwise at approximately the rate of decomposition of the quaternary ammonium hydroxide (Note 12). 

Several efficient procedures for alkene epoxidation using Oxone were reported, such as Oxone/aqueous NaOH, Oxone/acetone, Oxone/water , Oxone/PTC/benzene/ aqueous buffer solution or Oxone/2-butanone system. Thus, sorbic acid can be regioselectively oxidized using Oxone/aqueous NaOH to 4,5-epoxy-2-hexenoic acid in 84% yield. Similarly, cyclooctene is oxidized to cyclooctene oxide in 81% yield, just by stirring it with Oxone in water . 1-Dodecene is epoxidized in good yield by Oxone/PTC in benzene aqueous buffer solution. It is otherwise difficult to epoxidize 1-dodecene by other oxidizing reagents. ... 

The catalytic oxidation experiments were carried out in a round bottom flask equipped with condenser and stirrer. Typically, 6 or 12 mmol of substrate, 2 mmol bromobenzene (internal standard), 9 ml solvent (1,2-dichloroethane) and 100 mg zeolite (which contains typically around 2.9 pmol V (0.15wt%), TBHP/V ratio = 2070) were heated to 70°C, after which 6 mmol of TBHP in a 5.3 mmol chlorobenzene solution (which at the same time can function as an internal standard) were added to start the reaction. A sample was taken immediately afterwards. Before and during the reaction the mixture was purged with nitrogen for oxidations with cyclohexene and cyclooctene. Samples were filtrated over cotton wool and/or alumina, and triphenylphosphine was added to remove TBHP. In case of acetone as the solvent at 70°C, reactions were performed in a 50 ml autoclave and the reaction mixture was only purged with nitrogen before heating. After reaction TBHP was determined by iodometric titration. 

Product structure was shown by X-ray crystallography . Treatment of either [(l,5-COD)IrCl]2 or [(cyclooctene)2lrCl]2 with excess norbornadiene (NBD) in acetone at 25°C yields an.oligomeric material that, in turn, forms monomeric products of formulas Ir(NBD)3(acac) and Ir(NBD)3(PMe3)Cl when treated with acetylacetone-Na2C03 or PMe3, respectively. The structure of the former, established by X-ray crystallography, in addition to f/ -acac and j -NBD, contains an exo-trans-exo metalla-cycle, I . 

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