関連する実験動画

Updated: Jul 15, 2026

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors
09:45

Modification and Functionalization of the Guanidine Group by Tailor-made Precursors

Published on: April 27, 2017

安定したカルベンである1,3-ディ-テルト-ブチリミダゾール-2-イリデンの基本性は,THFで表される

Yeong-Joon Kim1, Andrew Streitwieser

  • 1Department of Chemistry, University of California, Berkeley, California 94720-1460, USA.

Journal of the American Chemical Society
|May 16, 2002
PubMed
まとめ

1,3-di-tert-butylimidazol-2-ylideneの基本性は,THFにおける炭化水素指標を使用して定量化されました. このN-ヘテロサイクリックカルベンは,潜在的な水素結合効果のために,DMSOにおいて著しく塩基性である.

さらに関連する動画

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals10:44

Isolating Free Carbenes, their Mixed Dimers and Organic Radicals

Published on: April 19, 2019

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

Preparation of Contiguous Bisaziridines for Regioselective Ring-Opening Reactions

Published on: July 28, 2022

関連する概念動画

Structure of Conjugated Dienes01:16

Structure of Conjugated Dienes

Introduction
Conjugated dienes are compounds characterized by the presence of alternating double and single bonds. In a conjugated system like 1,3-butadiene, the unhybridized 2p orbital on each carbon overlaps continuously, allowing the π electrons to be delocalized across the entire molecule. In contrast, this type of overlap does not occur in cumulated and isolated dienes, such as 2,3-pentadiene and 1,4-pentadiene, respectively. Instead, the π electrons remain localized between the double...
π Molecular Orbitals of 1,3-Butadiene01:24

π Molecular Orbitals of 1,3-Butadiene

Conjugated dienes have lower heats of hydrogenation than cumulated and isolated dienes, making them more stable. The enhanced stabilization of conjugated systems can be understood from their π molecular orbitals.
The simplest conjugated diene is 1,3-butadiene: a four-carbon system where each carbon is sp2-hybridized and has an unhybridized p orbital that contains an unpaired electron. According to molecular orbital theory, atomic orbitals combine to form molecular orbitals such that the number...
Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene01:17

Electrophilic 1,2- and 1,4-Addition of HX to 1,3-Butadiene

The electrophilic addition of hydrogen halides such as HBr to alkenes and nonconjugated dienes gives a single product as per Markovnikov’s rule.
Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control01:23

Electrophilic Addition of HX to 1,3-Butadiene: Thermodynamic vs Kinetic Control

The addition of a hydrogen halide to 1,3-butadiene gives a mixture of 1,2- and 1,4-adducts. Since more substituted alkenes are more stable, the 1,4-adduct is expected to be the major product. However, the product distribution is strongly influenced by temperature; low temperature favors the 1,2-adduct, whereas the 1,4-adduct is predominant at high temperature.
Stability of Conjugated Dienes01:28

Stability of Conjugated Dienes

Introduction
A comparison of the enthalpies of hydrogenation of dienes reveals that conjugated dienes release less heat on hydrogenation, rendering them more stable than their nonconjugated analogs.
Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene01:14

Electrophilic 1,2- and 1,4-Addition of X2 to 1,3-Butadiene

Electrophilic addition of halogens to alkenes proceeds via a cyclic halonium ion to form a 1,2-dihalide or a vicinal dihalide.