Merging Halogen-Atom Transfer (XAT) and Cobalt Catalysis to Override E2-Selectivity in the Elimination of Alkyl Halides: A Mild Route toward <i>contra</i>-Thermodynamic Olefins
作者:Huaibo Zhao、Alastair J. McMillan、Timothée Constantin、Rory C. Mykura、Fabio Juliá、Daniele Leonori
DOI:10.1021/jacs.1c06768
日期:2021.9.15
mechanistically distinct tactic to carry E2-type eliminations on alkyl halides. This strategy exploits the interplay of α-aminoalkyl radical-mediated halogen-atom transfer (XAT) with desaturative cobalt catalysis. The methodology is high-yielding, tolerates many functionalities, and was used to access industrially relevant materials. In contrast to thermal E2eliminations where unsymmetrical substrates give regioisomeric
Synthesis and chiroptical properties of some asymmetric planar cisoid dienes
作者:Albert W. Burgstahler、Dale L. Boger、Nandkishor C. Naik
DOI:10.1016/0040-4020(76)80042-7
日期:1976.1
3-dimethylenebornane (4b), (−)-borno[2,3-c]-2,5-diphenylcyclopenta-2,4-dien-1-one (9a), and related compounds are reported. A significant role is attributed to substituent chirality effects in these comparatively rigid, essentially planar cisoidconjugateddiene systems.
(+)-5α-雄甾烯-14,16-二烯(2),(-)-冰片酚[2,3 - b ]环戊-1,3-二烯(3),(+)-报道了2,3-二亚甲基冰片烷(4b),(-)-冰片[2,3 - c ] -2,5-二苯基环戊-2,4-二烯-1-酮(9a)以及相关化合物。在这些相对刚性的,基本上为平面的类固醇共轭二烯体系中,取代基的手性效应起着重要作用。
Kinetics and mechanism of azidomercuration of alkenes, cycloalkenes, and their derivatives with a mercuric acetate-sodium azide system
作者:V. R. Kartashov、T. N. Sokolova、A. Yu. Pavinskii、I. V. Timofeev、A. B. Radbil'
DOI:10.1007/bf00713611
日期:1995.12
The kinetics of azidomercuration of alkenes, cycioalkenes, and their derivatives with a Hg(OAc)2-NaN3 system (1 ∶ 1, 1 ∶ 2, and 1 ∶ 3) was studied. Based on the data on the product structure and kinetic results, it was concluded that HgOAcN3 and Hg(N3)2 play the role of azidomercuration reagents. The reactions with alkenes having a strained double bond occur by a concerted scheme. With nonstrained
作者:Fabrizio Fabris、Alessandro De Martin、Ottorino De Lucchi
DOI:10.1016/s0040-4039(99)01889-4
日期:1999.12
Naturally occurring (+)-camphor was converted into 2-bromobornene and metallated at the 3-position by lithium and trimethyltin. The latter tin derivative, treated with Cu(NO3)2·3H2O in THF affords the syn and anti cyclotrimers plus a number of byproducts. The rather unexpected formation of the anti stereoisomer plus the structure of several byproducts confirm a mechanistic proposal based on a SnSn
S,O‐Ligand Promoted
<i>meta</i>
‐C−H Arylation of Anisole Derivatives via Palladium/Norbornene Catalysis
作者:Verena Sukowski、Manuela van Borselen、Simon Mathew、M. Ángeles Fernández‐Ibáñez
DOI:10.1002/anie.202201750
日期:2022.8
A highly efficient meta-selective C−H arylation of aryl ethers has been realized by a new catalytic system based on palladium/norbornene (Pd/NBE) and an S,O-ligand. The reaction proceeds with a broad range of aryl ethers. For the first time, unsymmetrical meta-diarylation of aryl ethers was accomplished using a novel norbornene. The isolation of palladium intermediates provides insight to the mechanism