Photolysis of Diazo(3-thienyl)methane:  A Simple Synthesis of a Methylenecyclopropene

Albers, Reinhard; Sander, Wolfram

doi:10.1021/jo9612178

Cited by 19 publications

(23 citation statements)

References 16 publications

(26 reference statements)

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“…At λ > 280 nm, another acyclic isomer, propargyl thioketene ( 8 ), appears in the IR spectrum, accompanied by the decrease in the IR absorptions of 5 , 6 , and 9 (Figure S6). Our findings corroborate those described earlier by Sander and co-workers, 16 while adding some additional detail in terms of the conformational isomerism of pent-2-en-4-ynethial ( 5 and 6 ) and methylenecyclopropene derivatives ( 9 ). Our discovery of the shorter-wavelength chemistry that affords thioketene 8 is also new.…”

Section: Resultssupporting

confidence: 92%

“…In accord with the results of earlier studies, 16 the ring-opened product, Z- pent-2-en-4-ynethial ( 6 ), is the only species observed by IR spectroscopy (Figure S13). Careful examination of the spectrum establishes that both s-E and s-Z rotamers of 6 are present.…”

Section: Resultssupporting

confidence: 91%

“…This behavior explains the inability of Albers and Sander to observe carbene 13 in their study of the photochemistry of 3-thienyldiazomethane ( 1 ). 16 Our findings establish that carbene 13 is not stable to the photolysis conditions used in the earlier experiment ( λ > 435 nm).…”

Section: Resultssupporting

confidence: 63%

“…37 IR assignments are based upon comparison of experimental spectra with computed IR spectra (B3LYP/6-31G*), as well as comparison with previously reported spectral data of 9 and 12 . 16,38 EPR and UV/vis experiments, performed under analogous conditions, provide strong support for the assignment of triplet 3-thienylcarbene ( s-E - and s-Z- 13 ). The EPR spectrum of 13 affords direct evidence for the triplet species, and the spectroscopic features are generally consistent with those expected for an arylcarbene (Figure 1).…”

Section: Resultsmentioning

confidence: 82%

“…In the current study, we focus on the isomeric furyl- and thienylcarbenes, which have eluded detection and characterization to the present time. 16,17 These fundamental studies of reactive thienyl intermediates are also germane to an understanding of the electronic structure of doped states of thiophene derivatives—materials that have achieved wide use in conducting polymers and other electronic applications. 18–20 …”

Section: Introductionmentioning

confidence: 99%

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Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene

et al. 2012

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Photolysis (λ > 543 nm) of 3-thienyldiazomethane (1), matrix isolated in Ar or N2 at 10 K, yields triplet 3-thienylcarbene (13) and α-thial-methylenecyclopropene (9). Carbene 13 was characterized by IR, UV/vis, and EPR spectroscopy. The conformational isomers of 3-thienylcarbene (s-E and s-Z) exhibit an unusually large difference in zero-field splitting parameters in the triplet EPR spectrum (|D/hc| = 0.508 cm−1, |E/hc| = 0.0554 cm−1; |D/hc| = 0.579 cm−1, |E/hc| = 0.0315 cm−1). Natural Bond Orbital (NBO) calculations reveal substantially differing spin densities in the 3-thienyl ring at the positions adjacent to the carbene center, which is one factor contributing to the large difference in D values. NBO calculations also reveal a stabilizing interaction between the sp orbital of the carbene carbon in the s-Z rotamer of 13 and the antibonding σ orbital between sulfur and the neighboring carbon—an interaction that is not observed in the s-E rotamer of 13. In contrast to the EPR spectra, the electronic absorption spectra of the rotamers of triplet 3-thienylcarbene (13) are indistinguishable under our experimental conditions. The carbene exhibits a weak electronic absorption in the visible spectrum (λmax = 467 nm) that is characteristic of triplet arylcarbenes. Although studies of 2-thienyldiazomethane (2), 3-furyldiazomethane (3), or 2-furyldiazomethane (4) provided further insight into the photochemical interconversions among C5H4S or C5H4O isomers, these studies did not lead to the spectroscopic detection of the corresponding triplet carbenes (2-thienylcarbene (11), 3-furylcarbene (23), or 2-furylcarbene (22), respectively).

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Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 91%

Section: Resultssupporting

confidence: 63%

Section: Resultsmentioning

confidence: 82%

Section: Introductionmentioning

confidence: 99%

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Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene

et al. 2012

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Bamford‐Stevens Reaction

2010

Comprehensive Organic Name Reactions and Reagents

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This reaction is the transformation of ketones and aldehydes into alkenes through the base‐promoted thermal or photolytic decomposition of p ‐toluenesulfonylhydrazones of the corresponding ketones or aldehydes and is known as the Bamford–Stevens reaction. This reaction is also referred to as the Bamford–Stevens olefination. This reaction has wide applications in the preparation of alkenes. Strong bases have been used in this reaction. The alkenes that have been formed during this reaction are normally the thermodynamic product, i.e., the highly substituted alkenes, and depending on the reaction conditions (e.g., bases used, solvents), other types of products rather than alkenes can also be prepared.

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ChemInform Abstract: Photolysis of Diazo(3‐thienyl)methane: A Simple Synthesis of a Methylenecyclopropene.

Albers

Sander

1997

ChemInform

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Photolysis of Diazo(3-thienyl)methane: A Simple Synthesis of a Methylenecyclopropene

Cited by 19 publications

References 16 publications

Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene

Photochemistry of Furyl- and Thienyldiazomethanes: Spectroscopic Characterization of Triplet 3-Thienylcarbene

Bamford‐Stevens Reaction

ChemInform Abstract: Photolysis of Diazo(3‐thienyl)methane: A Simple Synthesis of a Methylenecyclopropene.

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