Light-induced formation of stable thietes

Gotthardt, Hans; Huss, O. M.

doi:10.1016/s0040-4039(01)95010-5

Cited by 17 publications

(3 citation statements)

References 3 publications

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“…The measured value of the C-S-C angle in this ring is 77.4(2)°. Very similar observations were reported previously for monocyclic thiete compounds [35,36]. Benzothietes usually behave as highly reactive and labile species, however, solid samples of o-quinone 7 could be stored for months on air at ambient conditions without significant changes.…”

Section: Synthesis and Characterization Of New O-quinone Derivativessupporting

confidence: 84%

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

Norkov

Cherkasov

Shavyrin

et al. 2021

Beilstein J. Org. Chem.

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The fused 1,3-dithiole spacer seems to be very suitable for the functionalization of sterically hindered o-quinones with additional groups capable of coordination of metal ions and/or possessing a redox activity. An effective method for the synthesis of sterically hindered o-quinones containing 1,3-diketonate, dinitrile and p-quinone-methide functional groups at the periphery of the ligand has been developed. The novel compounds have rigid and conjugated structures and exhibit properties typical of o-quinones. A study of their monoreduced semiquinone derivatives reveal that the spin density is delocalized across the whole molecule, including peripheral fragments. The first stable o-quinone derivative bearing an annulated thiete heterocycle has been isolated and characterized.

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Section: Synthesis and Characterization Of New O-quinone Derivativessupporting

confidence: 84%

Annulation of a 1,3-dithiole ring to a sterically hindered o-quinone core. Novel ditopic redox-active ligands

Norkov

Cherkasov

Shavyrin

et al. 2021

Beilstein J. Org. Chem.

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“…Generally, (2+2)-cycloaddition products are formed from triplet thiones. Also with acetylenes (2+2)photocycloaddition reactions are usually observed [4][5][6][7][8][9][10][11]. Only in a few cases (4+2)-cycloaddition products can be isolated [12,13] .…”

Section: Introductionmentioning

confidence: 99%

Cycloaddition Reactions of Substituted Allenes with Triplet Excited Aromatic Thiones: Product Formation and Reaction Mechanism

Kamphuis

Grootenhuis

Ruijter

et al. 1985

Israel Journal of Chemistry

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The reactivity of substituted allenes H2CCC(R)X towards three triplet aromatic thiones has been investigated. Product analysis reveal the formation of two (2+2)‐cycloaddition products the thietanes 3, 4 (E + Z) and occasionally of one (4+2)‐cycloaddition product, thiopyran derivative (Z)‐5, generally in high overall yields. Steady state measurements show that electron donating substituents in the allenic system enhance the overall reaction rate. There is little effect of solvent polarity on the reaction rate. The correlation between the relative reaction rates and the first adiabatic ionization energy of the substituted allenes is in accordance with the formation of an exciplex between the excited thione and that π‐bond of the allenic system which is conjugated with the substituent X. From this exciplex two isomeric allylic 1,4‐biradicals (Z)‐8 and (E)‐8 are probably formed. After inter‐system crossing, ring closure gives the thietanes 3, (E)‐4, (Z)‐4 and/or thiopyran derivative (Z)‐5. The ratio in which 3, (E)‐4, (Z)‐4 and (Z)‐5 are formed is explained by considering electronic and steric factors in the proposed reaction mechanism. Experiments with an optically active allene (+)‐PhC(H)CC(H)Me support the intermediacy of a non‐chiral relatively stable allylic 1,4‐biradical. At infinite allene concentration the quantum yield approaches 1, indicating no energy loss during the reaction. Thus no measurable disproportionation of the allylic biradicals (Z)‐8 and (E)‐8 occurs.

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“…In the course of our investigation a preliminary report on the crystal structure of a stable thiete, which did not contain any geometrical detail, was published by Gotthardt & Huss (1978). Also, we have determined the crystal structure on an unsymmetrically substituted thiete (Verhoeckx, Kroon, Brouwer & Bos, 1980), whose structure will be compared with that of the title compound.…”

Section: Introductionmentioning

confidence: 99%