The crystal structure of 2,3,6,7,7,8-hexamethyl-1,5-diphenyltetracyclo[3,3,0,0<sup>2,8</sup>,0<sup>3,6</sup>]octan-4-one

Biefeld, C.G.; Eick, H.A.

doi:10.1107/s056774087400450x

Cited by 3 publications

(1 citation statement)

References 19 publications

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“…The raw data were reduced as described previously (Biefeld & Eick, 1974) and considered for use in the refinement by the criterion I>2a(I). An absorption correction was considered unnecessary in view of the small /~.…”

Section: Dimer Amentioning

confidence: 99%

The crystal structures of two photodimers of 6,6-dimethyl-2,3-benzo-2,4-cycloheptadienone

Biefeld¹,

Barnett²

1974

Acta Crystallogr Sect B

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The structures of two photodimers of 6,6-dimethyl-2,3-benzo-2,4-cycloheptadienone, C26H2802, have been determined from room temperature X-ray diffractometer data. Dimer A crystallizes in the monoclinic space group C2/c with a= 30.141 (16), b= 8-536 (4), c= 15-979 (6) A and fl= 103.1 (2) ° and Z=8. Dimer B crystallizes in the monoclinic space group P2~/c with a = 7.774 (2), b = 15.503 (6), e = 16.752 (5) ,~ and fl= 100.95 (2) ° and Z= 4. Both structures were solved by direct methods and refined by blockdiagonal least-squares techniques to R values of 0.050 (1761 independent reflections) and 0-043 (1172 independent reflections) for dimer A and dimer B respectively. In both molecules the five-to six-membered ring juncture has been found to be cis and the six-to seven-membered ring juncture trans; however, in dimer A the hydrogen atoms H~ and Hc are trans, whereas, in dimer B they are cis. The location of strain in different regions of the two dimers is shown through a comparison of bond lengths and angles and dihedral angles. The conformations of the non-aromatic rings differ in the two molecules, those in dimer A being more flattened than those in dimer B.

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Section: Dimer Amentioning

confidence: 99%

The crystal structures of two photodimers of 6,6-dimethyl-2,3-benzo-2,4-cycloheptadienone

Biefeld¹,

Barnett²

1974

Acta Crystallogr Sect B

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Cyclobutanone und Cyclobutenone in der Natur und in der Synthese

Belluš

Ernst

1988

Angewandte Chemie

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Cyclobutanones and Cyclobutenones in Nature and in Synthesis [New Synthetic Methods(71)]

Belluš

Ernst

1988

Angew. Chem. Int. Ed. Engl.

247

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The chemical reactivity of cyclobutanones and cyclobutenones is considerably different from that of cyclic ketones with larger rings; this is due to their ring strain of ca. 25 kcal/mol. Detailed knowledge regarding the influence of this ring strain on regio‐, chemo‐ and stereoselective transformations of four‐membered ring ketones is of particular importance. While several reactions, such as the Baeyer–Villiger reaction, the Beckmann and Favorskii rearrangements and cine‐substitution often proceed in a manner specific to four‐membered rings, other reactions such as the facile ring‐opening by nucleophiles, the rearrangement to tropolones, the thermal [2+2]‐cycloreversion, the isomerization to vinylketenes and the photochemical formation of oxacarbenes are rather specific to cyclobutanones and cyclobutenones. The remarkable selectivity and the excellent yields of such transformations, which are favored or caused by ring strain as the inherent driving force, offer the synthetic chemist fascinating possibilities for the development of new strategies for the synthesis of natural products and biologically active compounds.

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The crystal structure of 2,3,6,7,7,8-hexamethyl-1,5-diphenyltetracyclo[3,3,0,0^2,8,0^3,6]octan-4-one

Cited by 3 publications

References 19 publications

The crystal structures of two photodimers of 6,6-dimethyl-2,3-benzo-2,4-cycloheptadienone

The crystal structures of two photodimers of 6,6-dimethyl-2,3-benzo-2,4-cycloheptadienone

Cyclobutanone und Cyclobutenone in der Natur und in der Synthese

Cyclobutanones and Cyclobutenones in Nature and in Synthesis [New Synthetic Methods(71)]

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The crystal structure of 2,3,6,7,7,8-hexamethyl-1,5-diphenyltetracyclo[3,3,0,02,8,03,6]octan-4-one

Cited by 3 publications

References 19 publications

The crystal structures of two photodimers of 6,6-dimethyl-2,3-benzo-2,4-cycloheptadienone

The crystal structures of two photodimers of 6,6-dimethyl-2,3-benzo-2,4-cycloheptadienone

Cyclobutanone und Cyclobutenone in der Natur und in der Synthese

Cyclobutanones and Cyclobutenones in Nature and in Synthesis [New Synthetic Methods(71)]

Contact Info

Product

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The crystal structure of 2,3,6,7,7,8-hexamethyl-1,5-diphenyltetracyclo[3,3,0,0^2,8,0^3,6]octan-4-one