cis-5-Cyclooctene-1,2-dione and its Ethylene Ketals

Abstract

Oxidation of cis-cis-1,s-cyclooctadiene with hydrogen peroxide gives cis-5-cyclooctene-trans-l,2-diol (3) which is converted to cis-5-cyclooctene-l,2-dione (6) on treatment with dimethyl sulfoxide and acetic anhydride. Bromination of 6 is accompanied by transannular bonding to give a dibromo keto ether 9a or b. Ketalization of 6 with ethylene glycol gives a monoketal 11 and two diketals 12 and 13 with 1,3-dioxolane and 1,4-dioxane rings, respectively. Bromination of 12 with bromine or pyridinium perbromide is accompanied by transannular bonding and fission of one of the 1.3-dioxolane rings to give a dibromo monoketal ether 15a (or b). Bromination of 12 with N-bromosuccinimide followed by dehydrobromination gives a cyclooctadiene-l,2-dione diketal20a (or b).L'oxydation par l'eau oxygCnCe du cyclooctadi6ne-1.5 cis-cis donne le cis-cyclooct6ne-5 diol-1,2 trans (3) qui est converti en cis-cyclooctitne-5 dione-1,2 (6) par traitement avec le dimCthylsulfoxyde et l'anhydride acetique. La bromation de 6 est suivie de la formation d'une liaison transannulaire pour conduire au dibromocetoether 9a ou b. La cetalisation de 6 avec l'ethyl6neglycol donne un monocetal 11 et deux dicetals 12 et 13 avec respectivement des cycles dioxolane-1,3 et dioxane-1,4. La bromation de 12 par le brome ou par le perbromure de pyridinium est suivie de la formation d'une liaison transannulaire et de la scission d'un des cycles dioxolane-1,3 pour donner un dibromo monocetalether 15a (ou b). La bromation de 12 par le Nbromosuccinimide suivie d'une dthydrobromation, conduit au cyclooctaditne dione-1,2 dicetal 20a (ou b).Canadian Journal of Chemistry, 50, 1548Chemistry, 50, (1972 In an earlier paper in this series (2) we discussed the interest underlying the chemistry of 1,2-cyclooctatetraenoquinone (1) and its 1,4 isomer as a result of their potential aromaticity. We described a synthesis of dibenzo[a,e]cyclooctene-5,6-diene (2), the dibenzo analogue of 1, and demonstrated that its eight-membered ring is not aromatic. It was pointed out that the latter observation could not be taken as implying the absence of aromaticity in the parent monocyclic compound 1, since the benzenoid rings of 2 might damp the aromaticity of the eightmembered ring (3). We report now on some synthetic approaches to 1, which, although not crowned with success, have provided results of interest in the area of eight-membered ring chemistry.Oxidation of cis-cis-1,5-cyclooctadiene with hydrogen peroxide and formic acid followed by basic hydrolysis gave cis-5-cyclooctene-trans- 1,2-diol (3) as a colorless oil in 55% yield. The stereochemistry is assigned as trans on the basis of analogy with analogous hydroxylation reactions (4). The preparation of this diol by hydrolysis of the corresponding epoxide has been reported previously in the patent literature (5) and in a review (6). The diol afforded an oily diacetate (4) and a crystalline dibrosylate (5); the spectra of 3-5 were in full accord with these structural assignments (see Experimental).Oxidation of 3 with dimethyl sulfo...

Synthesis of some cyclooctane-based pyrazines and quinoxalines

“…cis,cis-Cycloocta-1,5-diene was dihydroxylated, following earlier work, 11 by reaction with a mixture of hydrogen peroxide (33%) and formic acid at 40-45 °C giving 13 in 39% yield. Oxidation of the diol using dimethylsulfoxide activated with acetic anhydride produced the dione 14 (31% yield) and reaction of this with ortho-phenylenediamine in refluxing acetic acid gave the quinoxaline 15 in 88% yield (Scheme 6), these last two steps also having been described previously.…”

“…Intensity data were measured from a colourless crystal measuring 0.40x0.10x0.05 mm. (4) 7428 (8) 6223 (4) 5015 (3) 37(1) C (5) 9037 (8) 6597 (4) 4565 (3) 36(1) C (6) 9165 (7) 7809 (4) 4331 (3) 32(1) C (7) 10845 (8) 9315 (5) 3665 (3) 32(1) C (8) 12668 (7) 9698 (4) 3187 (3) 33(1) C (9) 12225 (8) 9611 (5) 2250 (3) 40(1) C (10) 10808 (10) 10658 (6) 1885 (4) 64(2) C (11) 8672 (10) 10563 (6) 2143(3) 57(2) C (12) 7933 (9) 11510 (5) 2723 (3) 44(1) C (13) 9137 (8) 11414 (4) 3570 (3) 34(1) C (14) 9221 (7) 10140 (4) 3881 (3) 28 (1) …”

Cyclooct‐1‐en‐5‐yne. Preparation, spectroscopic characteristics and chemical reactivity

“…Preparation and general properties. Cyclooct-1-en-5yne (3) was synthesized from cyclooct-5-ene-l,2-dione (1 1) [9] by oxidative degradation of its dihydrazone under exclusion of air (Scheme 2). Care should be taken to avoid the conversion of 11 to its hemiacetall2 in alcoholic solvents.…”

“…- The synthesis of 11 has been described by Yares et al [9]. In order to prevent the ready decomposition of its precursor diol 10 during hydrolysis and work-up, the procedure [9] was modified as follows: An ice-cooled solution of sodium hydroxide (150 g in 300 ml water) was cautiously added to the ice-cooled and stirred raw product (160 g) resulting from the oxidation of 1,5-cyclooctadiene (114 ml), keeping the temperature of the reaction mixture below 45" during, and at 45" for half an hour after the addition. The diol 10 was then extracted by washing with five portions of warm ethyl acetate (300 ml each, 45").…”

“…Where a comparison is possible, the reactivity of 3 is found to be considerably greater than that of 1 or 2. Apart from the oxidation product 11, the structure of which has been established by comparing its quinoxaline derivative 13 with an authentic sample [9], the products were identified on the basis of spectroscopic data. Some comments on individual reactions follow; details are given in the experimental part.…”