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Updated: Jun 19, 2026

Reductive Electropolymerization of a Vinyl-containing Poly-pyridyl Complex on Glassy Carbon and Fluorine-doped Tin Oxide Electrodes
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Published on: January 30, 2015

在乙烯基硫氧化物中的立体电子效应

Roland Ulshöfer1, Joachim Podlech

  • 1Karlsruher Institut für Technologie, Fritz-Haber-Weg 6, 76131 Karlsruhe, Germany.

Journal of the American Chemical Society
|November 6, 2009
PubMed
概括

乙烯基硫氧化物通过轨道对齐表现出独特的电子稳定性,影响紫外线吸收和核爱攻击的立体选择性. 这项研究量化了乙烯基硫氧化物反应中的这些差异.

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Preparation and Reactions of Sulfides

Sulfides are the sulfur analog of ethers, just as thiols are the sulfur analog of alcohol. Like ethers, sulfides also consist of two hydrocarbon groups bonded to the central sulfur atom. Depending upon the type of groups present, sulfides can be symmetrical or asymmetrical. Symmetrical sulfides can be prepared via an SN2 reaction between 2 equivalents of an alkyl halide and one equivalent of sodium sulfide.
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SN2 Reaction: Stereochemistry

In an SN2 reaction, the nucleophilic attack on the substrate and departure of the leaving group occurs simultaneously through a transition state. As the nucleophile approaches the substrate from the back-side, the configuration of the substrate carbon changes from tetrahedral to trigonal bipyramidal and then back to tetrahedral, leading to an inversion in the configuration of the product.
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Photochemical Electrocyclic Reactions: Stereochemistry

The absorption of UV–visible light by conjugated systems causes the promotion of an electron from the ground state to the excited state. Consequently, photochemical electrocyclic reactions proceed via the excited-state HOMO rather than the ground-state HOMO. Since the ground- and excited-state HOMOs have different symmetries, the stereochemical outcome of electrocyclic reactions depends on the mode of activation; i.e., thermal or photochemical.
Selection Rules: Photochemical Activation
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Stereochemical Effects of Enolization

The chiral α-carbon of the carbonyl compound is the stereocenter of the molecule. As shown in the figure below, when such a carbonyl compound undergoes racemization under an acidic or basic condition, an achiral enol is formed.
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Acid Halides to Esters: Alcoholysis

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Directing and Steric Effects in Disubstituted Benzene Derivatives

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