Olefins are prevalent substrates and functionalities. The synthesis of olefins from readily available starting materials such as alcohols, amines and carboxylic acids is of great significance to address the sustainability concerns in organic synthesis. Metallaphotoredox-catalyzed defunctionalizations were reported to achieve such transformations under mild conditions. However, all these valuable strategies
Electro‐mediated PhotoRedox Catalysis for Selective C(sp
<sup>3</sup>
)–O Cleavages of Phosphinated Alcohols to Carbanions
作者:Xianhai Tian、Tobias A. Karl、Sebastian Reiter、Shahboz Yakubov、Regina Vivie‐Riedle、Burkhard König、Joshua P. Barham
DOI:10.1002/anie.202105895
日期:2021.9.13
As well as deoxygenations, olefinations are reported which are E-selective and can be made Z-selective in a tandem reduction/photosensitization process where both steps are photoelectrochemically promoted. Spectroscopy, computation, and catalyst structural variations reveal that our new naphthalene monoimide-type catalyst allows for an intimate dispersive precomplexation of its radical anion form with
Nickel-Catalyzed Arylboration of Alkenylarenes: Synthesis of Boron-Substituted Quaternary Carbons and Regiodivergent Reactions
作者:Liang-An Chen、Alan R. Lear、Pin Gao、M. Kevin Brown
DOI:10.1002/anie.201904861
日期:2019.8.5
A method for the construction of boron‐substituted quaternary carbons or diarylquaternary carbons by arylboration of highly substituted alkenylarenes is presented. A wide range of alkenes and arylbromides can participate in this reaction thus allowing for a diverse assortment of products to be prepared. In addition, a solvent dependent regiodivergent arylboration of 1,2‐disubstituted alkenylarenes
Aryltriolborates as Air- and Water-Stable Bases for Wittig Olefination
作者:Wenhua Huang、Shuang-Hong Zhao、Ning Xu
DOI:10.1055/s-0034-1378919
日期:——
1-tris(hydroxymethyl)ethane, and aqueous tetrabutylammonium hydroxide. The aryltriolborates can be used as bases in Wittigreactions of aromatic aldehydes with all three types of phosphorus ylides: stabilized and semistabilized ylides can be generated at room temperature, and nonstabilizedylides at 120 °C (bath temperature). Tetrabutylammonium aryltriolborates have been synthesized in 37–66% yield by a one-pot
Et<sub>2</sub>Zn-Mediated Rearrangement of Bromohydrins
作者:Lezhen Li、Peijie Cai、Qingxiang Guo、Song Xue
DOI:10.1021/jo800231s
日期:2008.5.1
and highly efficient method for the rearrangement of bromohydrins mediated by Et2Zn to synthesize carbonylcompounds was described. Various β-bromo alcohols were treated with 0.6 equiv of Et2Zn to form a zinc complex in CH2Cl2 at room temperature for 2 h, followed by 1,2-migration to give the corresponding carbonylcompounds. This remarkable and clean rearrangement is general for acyclic and cyclic bromohydrins