Aliphatic diazo compounds. XIV. The synthesis of 7-substituted 3-diazo-2-norbornanones and the infrared and proton and carbon-13 nuclear magnetic resonance spectra of these diazo ketones and their precursors

Abstract

. 62, 1751 (1984).syn-and anti-7-lsopropyl-2-norbornanone (5 and 6) were prepared by catalytic hydrogenation of 7-isopropylidene-2-norbornanone; syri-and anti-7-benzhydryl-2-norbornane (9 and 10) were prepared in analogous fashion. Kctones 5 and 6 and syrl-and arlti-7-tert-butyl-2-norbornanone (7 and 8) were converted to the corresponding 3-diazo-2-norbornanones 1-4 via the monotosylhydrazones 44-47 of the corresponding a-diketones 40-43. The 'H and "C nmr spcctra of 1-10,40-47, and thcir precursors have been analyzed. The 'H nmr spectra of the diazo ketones 1-4 have their C-I and C-4 bridgehead proton signals shifted to higher and lower field, respectively, relative to the bridgehead signals of thc corresponding dikctones. Thc "C nmr spectra of all pairs of bicyclic epimers shown y-garrche shielding effects by the 7-substitucnt at (sp3) C-3 in thc syrl compounds and at C-5 and C-6 in the arlti compounds. A converse effect is found at (sp') C-2 (and C-3 in the diketoncs). Comparison of the magnitude of the shielding effects of C-7 methyl, isopropyl, benzhydryl, and tert-butyl substituents gives evidence of 6 deshielding effects at C-3 in the syrl compounds and at C-5 and C-6 in thc onti compounds by methyl substitucnts on C-8.PETER YATES et JOHN DAVID KRONIS. Can. J. Chem. 62, 1751 (1984.On a prCparC Ics isopropyl-7 norbornanones-2 syrl et anti (5 et 6) par hydrogenation catalytique de I'isopropylidene-7 norbornanone-2; on a prCparC les benzhydryl-7 norbornanones-2 syrl et nrlti (9 et 10) d'unc manikre semblablc. On a transform6 les cCtones 5 et 6 ainsi que les tert-butyl-7 norbornanones-2 sytl et anti (7 et 8) en leurs diazo-3 norbornanones-2 correspondantes (1-4) par le biais des monotosylhydrazones 44-47 des a-dicCtones correspondantes 40-43. On a analysC les spectrcs rmn du ' H et du "C des composCs 1-10 et 40-47 et de leurs prCcurseurs. Dans les spectres rmn du 'H des diazocCtones 1-4, les signaux des protons en tCte de pont (C-l et C-4) sont dCplacCs respectivcment vers des champs plus haut et plus bas, par rapport aux signaux des protons dans les positions Cquivalentes des dicttones correspondantes. Les spectrcs rmn du '.'c de chacune des paires d'Cpimkres bicycliques prtsentent tous des effets de blindage y-gauche, dus aux substituants en position 7 et affectant la position C-3 (sp3) des composCs syrl et les positions C-5 et C-6 dcs composts anti. On observe un effet inverse au niveau de C-2 (sp') (et de C-3 dans les dicttones). Une comparaison de I'amplitude dcs cffets de blindage provoquCs par les substituants mCthyle, isopropyle, benzhydrylc et tert-butyle en C-7 suggkre que les substituants mCthyles cn C-8 provoquent des effets de dtblindage 6 en C-3 dans les composCs syn et en C-5 et C-6 dans les composCs anti.[Traduit par le journal]In connection with our studies on the acid-catalyzed decomposition of a-diazo ketones (1, 2), we required pairs of 3-diazo-2-norbornanones with bulky syt7-and anti-7 substituents. We describe here the synthesis of the diazo ketones 1-4, prepared for this purpose, and di...

2-Chlorobicyclo[2.2.1]hept-5-ene-2-carboxamide and 2-chlorobicyclo[2.2.1]heptane-2-carboxamide as precursors of bicyclo[2.2.1]hept-5-en-2-one and bicyclo[2.2.1]heptan-2-one: resolution, absolute configuration and hydrogen-bonding properties

“…This compared well with the literature values. [26][27][28] The use of ZnI 2 29 or in situ generated Cu(I) as catalysts gave similar yields and the same exo/endo selectivity, consistent with previous studies. 30,6 When the chloronitrile 3 exo/endo mixture was subjected to aqueous basic conditions, the endo-CN isomer of 3 reacted more quickly to afford the corresponding endo a-chloro amide than did the exo-CN isomer.…”

Synthesis and Structure of Enantiomerically Pure Platinum Complexes of Phosphino-oxazolines and Their Use in Asymmetric Catalysis

“…We found that 5 mol % of complex 5a would catalyze the reaction shown to give high conversion to 9a and 9b as a 7:1 mixture of endo and exo isomers (Scheme ). NMR spectroscopy reveals that the endo-2-chloro isomer is favored (as is the case with the uncatalyzed reaction (4:1 mixture) 11c. The enantioselectivity of the process could be estimated by GC 12 and was always found to be low (ca.…”

“…An enantioselective version of the Diels−Alder reaction of acrylonitrile derivatives would be a very useful process, as the nitrile group is readily transformed into other functionalities. In the case of substrate 7 , the cyano and chloro groups can be simply converted to a carbonyl group, and it therefore acts as a useful ketene equivalent …”

Biological Activity of α-Thujaplicin, the Minor Component of Thujopsis dolabrata SIEB. et ZUCC. var. hondai MAKINO

“…Synthesis of 7,7-Dichloro-4-isopropylidene-bicyclo[3.2.0]-hept-2-en-6-ones To a stirred solution of freshly distilled 6,6-dimethylfilvene (70.0 g, 74.9%, 0.49 mol) 14) and dichloroacetylchloride (106.6 g, 0.72 mol) in n-hexane (500 ml) was added dropwise Et 3 N (72.8 g, 0.72 mol) over a period of 1 h. The mixture was stirred for an additional 6 h and allowed to stand overnight. The reaction mixture was washed with H 2 O (3ϫ300 g).…”

“…Measurement: The 1 H-NMR spectra were measured with a JEOL GSX-270 spectrometer using tetramethylsilane as an internal standard. HR-MS spectrum was measured with JEOL JMS-HX-100.Synthesis of 7,7-Dichloro-4-isopropylidene-bicyclo[3.2.0]-hept-2-en-6-ones To a stirred solution of freshly distilled 6,6-dimethylfilvene (70.0 g, 74.9%, 0.49 mol) 14) and dichloroacetylchloride (106.6 g, 0.72 mol) in n-hexane (500 ml) was added dropwise Et 3 N (72.8 g, 0.72 mol) over a period of ICR Building 2F, …”