Jove
Visualize
Contact Us
JoVE
x logofacebook logolinkedin logoyoutube logo
ABOUT JoVE
OverviewLeadershipBlogJoVE Help Center
AUTHORS
Publishing ProcessEditorial BoardScope & PoliciesPeer ReviewFAQSubmit
LIBRARIANS
TestimonialsSubscriptionsAccessResourcesLibrary Advisory BoardFAQ
RESEARCH
JoVE JournalMethods CollectionsJoVE Encyclopedia of ExperimentsArchive
EDUCATION
JoVE CoreJoVE BusinessJoVE Science EducationJoVE Lab ManualFaculty Resource CenterFaculty Site
Terms & Conditions of Use
Privacy Policy
Policies

Related Concept Videos

Photochemical Electrocyclic Reactions: Stereochemistry01:26

Photochemical Electrocyclic Reactions: Stereochemistry

2.4K
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
2.4K
Thermal and Photochemical Electrocyclic Reactions: Overview01:26

Thermal and Photochemical Electrocyclic Reactions: Overview

3.2K
Electrocyclic reactions are reversible reactions. They involve an intramolecular cyclization or ring-opening of a conjugated polyene. Shown below are two examples of electrocyclic reactions. In the first reaction, the formation of the cyclic product is favored. In contrast, in the second reaction, ring-opening is favored due to the high ring strain associated with cyclobutene formation.
3.2K
Thermal Electrocyclic Reactions: Stereochemistry01:17

Thermal Electrocyclic Reactions: Stereochemistry

2.7K
The stereochemistry of electrocyclic reactions is strongly influenced by the orbital symmetry of the polyene HOMO. Under thermal conditions, the reaction proceeds via the ground-state HOMO.
Selection Rules: Thermal Activation
Conjugated systems containing an even number of π-electron pairs undergo a conrotatory ring closure. For example, thermal electrocyclization of (2E,4E)-2,4-hexadiene, a conjugated diene containing two π-electron pairs, gives trans-3,4-dimethylcyclobutene.
2.7K
Dehydration of Aldols to Enones: Acid-Catalyzed Aldol Condensation00:43

Dehydration of Aldols to Enones: Acid-Catalyzed Aldol Condensation

3.2K
As shown in Figure 1, under acidic conditions, the β-hydroxy ketone undergoes dehydration via an E1 elimination reaction to form an enone.
3.2K
Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide02:44

Oxidation of Alkenes: Syn Dihydroxylation with Osmium Tetraoxide

13.6K
Alkenes are converted to 1,2-diols or glycols through a process called dihydroxylation. It involves the addition of two hydroxyl groups across the double bond with two different stereochemical approaches, namely anti and syn. Dihydroxylation using osmium tetroxide progresses with syn stereochemistry.
13.6K
Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids02:04

Oxidation of Alkenes: Anti Dihydroxylation with Peroxy Acids

8.1K
Diols are compounds with two hydroxyl groups. In addition to syn dihydroxylation, diols can also be synthesized through the process of anti dihydroxylation. The process involves treating an alkene with a peroxycarboxylic acid to form an epoxide. Epoxides are highly strained three-membered rings with oxygen and two carbons occupying the corners of an equilateral triangle. This step is followed by ring-opening of the epoxide in the presence of an aqueous acid to give a trans diol.
8.1K

You might also read

Related Articles

Articles linked to this work by shared authors, journal, and citation graph.

Sort by
Same author

Highly Selective and Modular Assembly of Densely Substituted Tetrahydrofurans.

Journal of the American Chemical Society·2026
Same author

Direct Regioselective para-Fluorination via I(I)/I(III) Catalysis.

Angewandte Chemie (International ed. in English)·2026
Same author

Accessing Medium-Sized Bridged Heterocycles via EnT-Catalyzed Intermolecular Dearomative (5 + 4) Cycloaddition of Furans and Oxazoles.

Journal of the American Chemical Society·2026
Same author

Energy-Transfer Catalysis Enables the Birch-Type Reduction of 2-Pyridones.

Angewandte Chemie (International ed. in English)·2026
Same author

Fluorinated carbohydrate-based vaccines.

Chemical science·2026
Same author

Diastereoselective synthesis of 1,4,8-trisubstituted perhydroquinolines as novel κ receptor agonists.

Organic & biomolecular chemistry·2026

Related Experiment Video

Updated: Apr 4, 2026

Light-driven Enzymatic Decarboxylation
09:58

Light-driven Enzymatic Decarboxylation

Published on: May 22, 2016

12.4K

Photocatalytic, Regioselective Enone Deconjugation: An Enabling Platform for Terpene Modification.

Lukas Blank1, Christian Mück-Lichtenfeld1, Constantin G Daniliuc1

  • 1Institute for Organic Chemistry, University of Münster, Corrensstraβe 36, 48149 Münster, Germany.

Journal of the American Chemical Society
|April 2, 2026
PubMed
Summary

This study introduces a photocatalytic method for alkene isomerization, overcoming synthetic challenges. The new approach efficiently synthesizes valuable compounds like beta-isophorone and steroid precursors using green light.

More Related Videos

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
07:12

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Published on: July 17, 2020

6.8K
Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols
10:12

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Published on: April 4, 2014

13.8K

Related Experiment Videos

Last Updated: Apr 4, 2026

Light-driven Enzymatic Decarboxylation
09:58

Light-driven Enzymatic Decarboxylation

Published on: May 22, 2016

12.4K
Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions
07:12

Cercosporin-Photocatalyzed [4+1]- and [4+2]-Annulations of Azoalkenes Under Mild Conditions

Published on: July 17, 2020

6.8K
Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols
10:12

Retropinacol/Cross-pinacol Coupling Reactions - A Catalytic Access to 1,2-Unsymmetrical Diols

Published on: April 4, 2014

13.8K

Area of Science:

  • Organic Chemistry
  • Photocatalysis
  • Synthetic Methodology

Background:

  • Alkene isomerization is crucial in biology but synthetically challenging due to thermodynamic and regiochemical hurdles.
  • Existing methods for ground-state positional isomerization are limited.
  • Light-based activation offers a route to overcome selectivity issues by utilizing excited-state reactivity.

Purpose of the Study:

  • To develop a mild photocatalytic method for alkene deconjugation and isomerization.
  • To mimic the biochemical function of steroid Δ5-isomerase.
  • To enable regioselective synthesis of valuable chemical intermediates.

Main Methods:

  • Utilized a traceless C(sp3)-Br handle to bias regioselective generation of a photodienol intermediate.
  • Employed green light (520 nm) irradiation.
  • Used an organophotoredox catalyst (eosin Y), a base (NaOAc), and a sacrificial reductant (HEH2).

Main Results:

  • Achieved endo-selective debrominative deconjugation of diverse brominated cyclic enones.
  • Successfully synthesized β-isophorone, a precursor for vitamins and carotenoids.
  • Generated 3-oxo-Δ5-steroids, relevant to hormones and oncology drugs.

Conclusions:

  • The developed photocatalytic method provides efficient access to structurally diverse alkenes.
  • This approach overcomes limitations in ground-state isomerization and mimics biological processes.
  • The method facilitates the synthesis of industrially relevant compounds and pharmaceutical intermediates.