布鲁克重新排列作为Dearomatization反应的触发器:非芳香N-异环环的合成

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...

In the presence of an aqueous base and a halogen, primary amides can lose the carbonyl (as carbon dioxide) and undergo rearrangement to form primary amines. This reaction, called the Hofmann rearrangement, can produce primary amines (aryl and alkyl) in high yields without contamination by secondary and tertiary amines.

Nucleophilic substitution in aromatic compounds is feasible in substrates bearing strong electron-withdrawing substituents positioned ortho or para to the leaving group. The reaction proceeds via two steps: the addition of the nucleophile and the elimination of the leaving group.
The reaction begins with an attack of the nucleophile on the carbon that holds the leaving group. This results in the delocalization of the π electrons over the ring carbons. The resonance interaction between...

The Cope rearrangement is classified as a [3,3] sigmatropic shift in 1,5-dienes, leading to a more stable, isomeric 1,5-diene. The reaction involves a concerted movement of six electrons, four from two π bonds and two from a σ bond, via an energetically favorable chair-like transition state.

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...

The addition of hydrogen bromide to alkenes in the presence of hydroperoxides or peroxides proceeds via an anti-Markovnikov pathway and yields alkyl bromides.