Synthesis of Polyfunctionalized Triaryllanthanum Reagents by Using Ph<sub>3</sub>
La and Related Species as Exchange Reagents
作者:Andreas D. Benischke、Lucile Anthore-Dalion、Fabien Kohl、Paul Knochel
DOI:10.1002/chem.201801527
日期:2018.8.1
Ph3La⋅5 LiCl and the related (m‐xylyl)3La⋅5 LiCl were used as Hal/La exchange reagents (Hal=Br, I) for the preparation of various triaryl‐ and triheteroaryl‐lanthanum derivatives. These new exchange reagents are compatible with isoquinolines and some functional groups such as a nitrile or an ester. The reactivity of the resulting lanthanum compounds towards electrophiles, such as ketones, aldehydes
The Halogen–Samarium Exchange Reaction: Synthetic Applications and Kinetics
作者:Lucile Anthore‐Dalion、Andreas D. Benischke、Baosheng Wei、Guillaume Berionni、Paul Knochel
DOI:10.1002/anie.201814373
日期:2019.3.18
Fast I/Sm and Br/Sm exchanges take place when various aromatic or heterocyclic iodides and bromides are treated with nBu2SmCl⋅4 LiCl and nBu3Sm⋅5 LiCl, respectively. The resulting organosamarium reagents were efficiently quenched with aldehydes, ketones, and imines. Also, they undergo acylations when treated with N,N‐dimethylamides leading to ketones. The rate of the Br/Sm exchange for a typical aryl
当分别用n Bu 2 SmCl·4 LiCl和n Bu 3 Sm·5 LiCl处理各种芳族或杂环碘化物和溴化物时,会发生快速的I / Sm和Br / Sm交换。将所得有机sa试剂有效地用醛,酮和亚胺淬灭。同样,当用N,N-二甲基酰胺处理时,它们会发生酰化反应,生成酮。确定了典型的芳基溴的Br / Sm交换速率,发现其比Br / Mg交换快8.5×10 5,这表明金属交换速率与碳的离子特性有关。金属键和对金属的电负性。
Co
<sup>I</sup>
‐Catalyzed Barbier Reactions of Aromatic Halides with Aromatic Aldehydes and Imines
作者:Marc Presset、Jérôme Paul、Ghania Nait Cherif、Nisanthan Ratnam、Nicolas Laloi、Eric Léonel、Corinne Gosmini、Erwan Le Gall
DOI:10.1002/chem.201806239
日期:2019.3.21
The reductive Barbier coupling of aromatic halides and electrophiles has been achieved using a CoBr2/1,10‐phenanthroline catalytic system and over stoichiometric amounts of zinc. The reaction displayed a broad scope of substrates, including (hetero)aryl chlorides as pro‐nucleophiles and aldehydes or imines as electrophiles, leading to diarylmethanols and diarylmethylamines in moderate to excellent
Triflimide-catalyzed allylsilane annulations of benzylic alcohols for the divergent synthesis of indanes and tetralins
作者:Jordan C. T. Reddel、Weiwei Wang、Kalli Koukounas、Regan J. Thomson
DOI:10.1039/c6sc04762a
日期:——
development of a triflimide-catalyzed annulation of benzylic alcohols with allylsilanes for the synthesis of indane or tetralin structures is reported. In this fragment coupling reaction, complexity is built rapidly from readily available starting materials to yield diverse sets of products with up to three contiguous stereocenters. Indanes or tetralins can be generated from common precursors depending
Picosecond Kinetic Study of the Photoinduced Homolysis of Benzhydryl Acetates: The Nature of the Conversion of Radical Pairs into Ion Pairs
作者:Libby R. Heeb、Kevin S. Peters
DOI:10.1021/ja077105n
日期:2008.2.6
conversion of benzhydryl acetate geminate radical pairs to contact ionpairs following photoinduced homolysis in solution is studied using picosecond pump-probe spectroscopy. The dynamics for the decay of the geminate radical pairs into contact ionpairs is modeled within a Marcus-like theory for nonadiabatic electron transfer. A second decay channel for the geminate radical pairs is diffusional separation