Photochemistry of bicyclic δ-thia-α,β-unsaturated ketones a vinylketene mechanism

Miyashi, Tsutomu; Suto, Nobukazu; Yamaki, Takayuki; Mukai, Toshio

doi:10.1016/s0040-4039(01)82973-7

Cited by 12 publications

(4 citation statements)

References 11 publications

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“…Similar light-induced 6 -4 ring contractions for S-heterocycles had been observed in studies on the photochemistry of isothiochroman-4-one [3] [4] and bicyclic S-thia-a,P-unsaturated ketones [5] [6]. In this latter study, the authors proposed that the formal 1,3-S migration might occur via a vinylketene intermediate, but no further mechanistic details were discussed.…”

supporting

confidence: 58%

Photoisomerization of 2H,6H‐Thiin‐3‐ones to 2‐(Alk‐1‐enyl)thietan‐3‐ones

Margaretha

1992

Helvetica Chimica Acta

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Reaction of 3-bromo-3-methylbutan-2-one (1) with mercapto-esters 2 affords 5-0x0-3-thiahexanoates 3 which cyclize to thiane-3,5-diones 4. Conversion of these dicarbonyl compounds to their ethyl en01 ethers 5-7 followed by reduction with LiAlH, gives 2H,6H-thiin-3-ones &lo. On irradiation (350 nm) in either MeCN, benzene, or i-PrOH, these newly synthesized heterocycles isomerize efficiently to 2-(alk-1 -enyl)thietan-3-ones 11-13. The rearrangement seems to proceed from an excited singlet state, as it is not quenched by naphthalene, and also occurs with the same efficiency in the presence of added alkene. A (94-3) sulfuranyl-alkyl biradical formed by bonding of C(n) of the enone C=C bond on sulfur is discussed as possible intermediate.

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supporting

confidence: 58%

Photoisomerization of 2H,6H‐Thiin‐3‐ones to 2‐(Alk‐1‐enyl)thietan‐3‐ones

Margaretha

1992

Helvetica Chimica Acta

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“…The photolysis of the δ-thia-α,β-unsaturated ketone 328 resulted in the formation of thietan-3-one 330 . , The overall reaction consisted of a 1,3-migration of the sulfur atom. Further evidence was supplied that the reaction took place via a [2+2]-cycloaddition of the vinylketene intermediate 329 …”

Section: A2 Synthesis By Ring Transformationsmentioning

confidence: 99%

“…Further evidence was supplied that the reaction took place via a [2+2]cycloaddition of the vinylketene intermediate 329. 230 Reaction of cyclic disulfides with carbenes, generated from catalytic or photochemical decomposition of diazo compounds, resulted in the formation of tetrasubstituted thietan-3-ones (Scheme 89, Table 5). 232 The products 332 resulted from S-S insertion of the disulfide and subsequent desulfurization.…”

Section: A2 Synthesis By Ring Transformationsmentioning

confidence: 99%

The Chemistry of Azetidin-3-ones, Oxetan-3-ones, and Thietan-3-ones

et al. 2001

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I. Introduction 29 II. The Chemistry of Azetidin-3-ones 29 A. Structural Data 29 B. Synthetic Methods for Azetidin-3-ones 31 B.1. Carbonyl Group Generation in the Azetidine Ring 31 B.2. Intramolecular Cyclization Reactions 34 B.3. 1,3-Dipolar Cycloaddition Reactions 36 C. Chemical Properties of Azetidin-3-ones 37 C.1. Transformations of the Carbonyl Group 37 C.2. Condensation Reactions − Synthesis of 2-Benzylideneazetidin-3-ones 40 C.3. Ring Transformations of Azetidin-3-ones 40 C.4. Miscellaneous 41 III. The Chemistry of Oxetan-3-ones 42 A. Structural Data 42 B. Synthetic Methods for Oxetan-3-ones 43 B.1. Decomposition of Diazoketones 43 B.2. Oxidation Reactions 44 B.3. Intramolecular Displacement Reactions 46 B.4. Miscellaneous 47 C. Chemical Properties of Oxetan-3-ones 48 C.1. Ring Opening and Ring Expansion of Oxetan-3-ones 48 C.2. Transformations of the Carbonyl Group 49 IV. The Chemistry of Thietan-3-ones 50 A. Synthetic Methods for Thietan-3-ones 51 A.1. Synthesis from Acyclic Precursors 51 A.2. Synthesis by Ring Transformations 53 B. Chemical Properties of Thietan-3-ones 54 B.1. Transformations of the Carbonyl Group 55 B.2. Aldol Reactions 56 B.3. Ring Transformations 56 V. Acknowledgments 58 VI. References 58

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“…A strategy toward synthesis of benzo[ b ]thiophenes via tandem thien- and benz-annulations of simple acyclic precursors is an appealing alternative but has not been developed. To the best of our knowledge, up to now, there has been only one single example reported by Mukai wherein pyrolysis of bicyclic δ-thia-α,β-unsaturated ketone at 520 °C afforded 4-hydroxybenzo[ b ]thiophene in 28% yield . Although it remains unexploited, this strategy would be highly desirable because it would avoid using prefunctional aromatic ring substrates and the functional groups could be directly introduced onto the benzo[ b ]thiophene skeletons by choosing appropriate substrates.…”

mentioning

confidence: 99%