Dehalogenation of halogenobicyclo-[2.2.1]-heptane derivatives - I new routes to benznorbornene and related compounds

Ring enlargements. XIII. Intramolecular diazoalkane-carbonyl reactions

“…Found: C, 56.76; H, 7.43; N, 16.46. Treatment of 6 with boiling nitric acid left it unchanged, in accordance with the bridged ring structure. 4 A third 50-ml portion of the solution of 5c was treated at -10 to -5°with 1 g of potassium carbonate in 100 ml of anhydrous ethanol and yielded 2.0 g of 4c and 1.9 g of a colorless liquid, bp 110-124°(0.5 mm), which was shown by glc on column 312 to consist of 92% of equal quantities of 6 and 3-(l'-carbethoxy-2'-ketocyclopentyl)propene-l (8), obtained as a colorless liquid: ir (liquid) 3120 (=CH), 1752 (cyclopentanone C=0), 1726 (ester C=0), and 1639 cm"1 (C=C); nmr (CC14) <5 1.26 (t, 3, J = 7.1…”

“…Thus, potassium carbonate induced decomposition of 5c at 25°g ives a mixture containing 1-carbethoxybicyclo[3.2.1]octan-8-one (6) and 1,4-dicarbethoxycycloheptanone (7), the alcoholysis product from 6. The structure of 6 is commensurate with a CuHieOg molecular formula, infrared stretching bands at 1760 and 1730 cm™1 for cyclopentanone and ester carbonyl functions, the observed nmr spectrum, and the failure to undergo oxidative cleavage with nitric acid. 4 The structure of 7 is commensurate with a C13H22O4 molecular formula, a single stretching band at 1742 cm-1 for identical ester carbonyl functions, and the nmr spectrum showing a pair of identical OCH2CH3 functions.…”

“…4 The structure of 7 is commensurate with a C13H22O4 molecular formula, a single stretching band at 1742 cm-1 for identical ester carbonyl functions, and the nmr spectrum showing a pair of identical OCH2CH3 functions. Under the more strenuous conditions of sodium ethoxide induced decomposition at 40-45°, 7 is the sole product, whereas under the milder conditions of potassium carbonate at -10°the bridged ring ketone 6 and the olefin 8 are formed in approximately equal amount.…”

“…Alkylation of 2-carbethoxycyclohexanone with chloroacetonitrile and sodium in refluxing toluene yielded 53% of 2-c~anomethyl-2-carbethox~c~-elohexanone (2b) as a colorless liquid: bp 98-103" (0.08 mm); ir (liquid) 2275 (CN), 1742 (ester C=O), 1720 cm-1 (cyclohexanone C=O); nmr (cc14) 6 The ethylene ketal 3b was prepared by the procedure described below for 3c and was obtained in 75% yield as a colorless liquid: Reductive acetylation of a 26.6-g sample of 3b, as described below for 3c, followed by selective hydrolysis yielded 23.0 g (90%) of N-acetyl-2-( l'-carbethoxy-2'-ketocyclohexyl)ethylamine (4b) as a pale yellow, viscous liquid that could not be distilled without decomposition. Nitrosation yielded an orange oil which was dissolved in 150 ml of methylene chloride.…”

“…Base-induced decomposition of the compounds carrying two-carbon side chains (5a and 5b) results in the formation of complex mixtures which were not investigated further, Base-induced decompositions of the compounds carrying three-carbon side chains (5c and 5d), on the other hand, proceed smoothly and yield more' tractable reaction mixtures. Thus, potassium carbonate induced decomposition of 5c at 25" gives a mixture containing l-carbethoxybicyclo[3.2.1]octan-8-one (6) and 1,4-dicarbethoxycycloheptanone (7), the alcoholysis product from 6. The structure of 6 is commensurate with a CllH1603 molecular formula, infrared stretching bands at 1760 and 1730 cm-l for cyclopentanone and ester carbonyl functions, the observed nmr spectrum, and the failure to undergo oxidative cleavage with nitric acid.…”