Related Experiment Video

Updated: Oct 30, 2025

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides
07:50

Efficient Synthesis of All-Carbon Quaternary Centers via the Conjugate Addition of Functionalized Monoorganozinc Bromides

Published on: May 26, 2019

9.5K

Directed regioselective ortho,ortho'-magnesiations of aromatics and heterocycles using sBu2Mg in toluene

Andreas Hess1, Jan P Prohaska1, Sabrina B Doerrich1

  • 1Ludwig-Maximilians-Universität München, Department Chemie Butenandtstrasse 5-13, Haus F 81377 München Germany paul.knochel@cup.uni-muenchen.de.

Chemical Science
|July 5, 2021
PubMed

More Related Videos

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions04:38

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Published on: July 28, 2022

3.2K
Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions08:56

Synthesis of a Borylated Ibuprofen Derivative Through Suzuki Cross-Coupling and Alkene Boracarboxylation Reactions

Published on: November 30, 2022

3.0K

Related Concept Videos

Regioselectivity and Stereochemistry of Hydroboration02:36

Regioselectivity and Stereochemistry of Hydroboration

A significant aspect of hydroboration–oxidation is the regio- and stereochemical outcome of the reaction.
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
8.6K
ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH301:11

ortho–para-Directing Activators: –CH3, –OH, –⁠NH2, –OCH3

All ortho–para directors, excluding halogens, are activating groups. These groups donate electrons to the ring, making the ring carbons electron-rich. Consequently, the reactivity of the aromatic ring towards electrophilic substitution increases. For instance, the nitration of anisole is about 10,000 times faster than the nitration of benzene. The electron-donating effect of the methoxy group in anisole activates the ortho and para positions on the ring and stabilizes the corresponding...
6.7K
Directing Effect of Substituents: ortho–para-Directing Groups01:14

Directing Effect of Substituents: ortho–para-Directing Groups

Ortho–para directors are substituent groups attached to the benzene ring and direct the addition of an electrophile to the positions ortho or para to the substituent. All electron-donating groups are considered ortho–para directors. They donate electrons to the ring and make the ring more electron-rich. The ring is therefore susceptible to the addition of electrophiles. Substituents such as amino, hydroxy, or alkoxy, containing lone pairs on the atom adjacent to the ring, donate...
7.5K
Directing and Steric Effects in Disubstituted Benzene Derivatives01:18

Directing and Steric Effects in Disubstituted Benzene Derivatives

When disubstituted benzenes undergo electrophilic substitution, the product distribution depends on the directing effect of both substituents. When the directing effects of both substituents reinforce each other, a single product is obtained. For example, bromination of p-nitrotoluene occurs ortho to the methyl group and meta to the nitro group, which is the same position, resulting in a single product. However, if the directing effects of the two groups oppose each other, the...
3.6K
Radical Anti-Markovnikov Addition to Alkenes: Overview01:25

Radical Anti-Markovnikov Addition to Alkenes: Overview

The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.
3.7K
Regioselectivity of Electrophilic Additions-Peroxide Effect02:35

Regioselectivity of Electrophilic Additions-Peroxide Effect

In the presence of organic peroxides, the addition of hydrogen bromide to an alkene yields the isomer that is not predicted by Markovnikov’s rule. For example, the addition of hydrogen bromide to 2-methylpropene in the presence of peroxides gives 1-bromo-2-methylpropane. This addition reaction proceeds via a free radical mechanism, which reverses the regioselectivity. The free radical reaction mechanism involves three stages: initiation, propagation, and termination.
9.2K