<i>En Route</i> to Multisurface Chemistry

Quinkert, Gerhard

doi:10.1002/anie.197507901

Cited by 42 publications

(9 citation statements)

References 34 publications

(2 reference statements)

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“…1.3.1.1.3), photochemist's experience excludes the triplet spin isomer lo). lo) See [25], Sect. 3.1, for the meanings of the terms electronic isomer and spin isomer.…”

Section: 24)mentioning

confidence: 99%

“…( 3Z,5E)-6-Acetoxy-N-~~y~~-eruyl-4-isopropyl-8-oxono~-3,5-d~ne~~ ( = (1 E,3Z)-6-(&tuykunino)-3-isopropyi-6-oxo-l-(2-oxopropyl) 95 (d, J((H-CH,),CH, (CH,),C-H) = 6.9, Me,CH); 1.64, 1.68 (2s, 3 H-C(9), MeCO,); 2.23 (sept., J(Me,CH, (H-CH,),CH) = 6.9, Me,CH); 2.90 (d,J(H-C (2),H-C(3)) = 7.6, 2 H-C(2)); 3.25 (s,2 H-C (7)); 4. 25 calc. for C,, H,,NO,(357.45): C 70.56,H 7.61,N 3.92;found: C 70.35,H 7.50,N 3.94.…”

Section: -6-(cyclohexylamin0)-6-0~0-~-(2oxopropyl)hexa-13-dien-f-ylmentioning

confidence: 99%

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ChemInform Abstract: Stereoselective Ring Opening of Electronically Excited Cyclohexa‐2,4‐ dienones: Cause and Effect.

Quinkert

1997

ChemInform

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The two conformers of a cyclohexa-2,4-dienone with different substituents at C(6) on irradiation are believed to undergo ring opening stereospecifically affording a mixture of two configurationally isomeric diene-ketenes (and descendents thereof). Exceptions are generally found for those dienones with one C and one 0 substituent or even with two C substituents, if one of them carries a polar group at a site able to interact through space with the ring C=O group. In these cases, only one of the two anticipated diene-ketenes (and descendents thereof) is produced. A thorough investigation of the photochemistry of a series of structurally different cyclohexa-2,4-dienones on analytical as well as on preparative scale extends our mechanistic knowledge of the various routes from diene-ketenes into a variety of compound classes. Novel compound classes accessible to diene-ketenes are seven-membered carbocycles (by intramolecular aldolization of the zwitterion of appropriately substituted, transiently formed diene-(N,O)-ketene acetals) and j-lactams (by Staudinger reaction).

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“…1.3.1.1.3), photochemist's experience excludes the triplet spin isomer lo). lo) See [25], Sect. 3.1, for the meanings of the terms electronic isomer and spin isomer.…”

Section: 24)mentioning

confidence: 99%

Section: -6-(cyclohexylamin0)-6-0~0-~-(2oxopropyl)hexa-13-dien-f-ylmentioning

confidence: 99%

ChemInform Abstract: Stereoselective Ring Opening of Electronically Excited Cyclohexa‐2,4‐ dienones: Cause and Effect.

Quinkert

1997

ChemInform

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“…Wahrend [24]: Abschnitt 3. I ) verstehen wir (Cyclohexadienon-)-Molekule, die sich durch ihre Elektronenstruktur (des Grundzustands oder der angeregten Zustande hauptsachlich rnit n *, n-oder vornehmlich rnit n*, n-Charakter) voneinander unterscheiden.…”

Section: ( Rs)-6-acetoxy-2346-tetramethyl-24-cyclohexadien-i-on (unclassified

“…I ) verstehen wir (Cyclohexadienon-)-Molekule, die sich durch ihre Elektronenstruktur (des Grundzustands oder der angeregten Zustande hauptsachlich rnit n *, n-oder vornehmlich rnit n*, n-Charakter) voneinander unterscheiden. Als Spinisomere (s. [24]: Abschnitt 3.1) bezeichnen wir elektronen-angeregte (Cyclohexadienon-)Molekule ein und derselben Elektronenstruktur entweder rnit Singulett-oder mit Triplett-Charakter. Die detaillierte Schilderung einer licht-induzierten Reaktion beginnt mit der Lichtabsorption der Reaktanden.…”

Section: ( Rs)-6-acetoxy-2346-tetramethyl-24-cyclohexadien-i-on (unclassified

Über Dienketene aus o‐Chinolacetaten

Quinkert

Kleiner

Freitag

et al. 1986

Helvetica Chimica Acta

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(RS)- 6-acetoxl.-5,.6-dimeth?.l-, (RS)-6-ucetoxy-2,4,6-1rimeth~.l-, 3,4,6-tet r m n i 4 i j~l -. and (RS)- 6-oci~tox~-2,3,4,5,6-pentumeth~l-2,4-c~clo/ie.~udii~n-I-oni~.~ serve as representative educts.Thcrc arc two separate main photochemical routes conveniently designated as l(n*, n) or '(n*, n ) tracks. The latter may also he attained by sensitization and leads to phenols. The former, by a-cleavage furnishes dien-ketens as indispensable phototransients. Photolysis of dien-ketens follows one or more of three reaction channels, each of which yields a particular type of photoproduct: heat-induced monocyclization affords 2,4-cyclohexadien-1-ones, heat-induced hicyclization stereoselectively furnishes bicyclo[3.1.0]hex-3-en-2-ones, and multi-step addition of protic nucleophiles stereosclcctively gives l,4-, I,6-and/or 1,2-adducts. By X-ray analysis or NOE studies, the structure of isolated photoproducts is establishcd. Conventional spectroscopy at low or flash spectroscopy at normal temperature yield information on the Cormation and decay of kinetically unstable intermediates. Photoproduct composition depends on the pattern o C substitution of the educts, o n thc solvents, and on the nucleophiles that might he present. Substituents primarily exert an influence upon the population of the various conformers of the dien-ketcn. Solvents affect the rate of the divers reaction paths competing for the phototransient. Nucleophiles play more than a trivial role when adducts are formed. With the detailed view of a dien-keten's role on hand, the photoproduct from a given o-quinol-acetate -or more general from a linear conjugatcd cyclohexadienone -is now predictable.

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“…The different chemical behavior of excited molecules in the singlet and the triplet state led to the concept of 'spinisomers', a phenomenon introduced to the chemical literature by Turro [6] and Quinkert. [7].…”

mentioning

confidence: 99%

Synthesis and Modifications of Amino Acids and Peptides via Diradicals

Wessig¹

2001

Radicals in Organic Synthesis

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En Route to Multisurface Chemistry

Cited by 42 publications

References 34 publications

ChemInform Abstract: Stereoselective Ring Opening of Electronically Excited Cyclohexa‐2,4‐ dienones: Cause and Effect.

ChemInform Abstract: Stereoselective Ring Opening of Electronically Excited Cyclohexa‐2,4‐ dienones: Cause and Effect.

Über Dienketene aus o‐Chinolacetaten

Synthesis and Modifications of Amino Acids and Peptides via Diradicals

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