Gold‐catalyzed [4+2] Annulations of Dienes with Nitrosoarenes as 4 π Donors: Nitroso‐Povarov Reactions
作者:Ching‐Nung Chen、Rai‐Shung Liu
DOI:10.1002/anie.201903615
日期:2019.7.15
This work reports the first success of the nitroso‐Povarov reaction, involving gold‐catalyzed [4+2] annulations of nitrsoarenes with substituted cyclopentadienes. In this catalytic sequence, nitrosoarenes presumably attack gold‐π‐dienes by a 1,4‐addition pathway, generating allylgold nitrosonium intermediates to complete an intramolecular cyclization. Acyclic dienes are also applicable substrates,
Gold‐Catalyzed [3+2]‐Annulations of α‐Aryl Diazoketones with the Tetrasubstituted Alkenes of Cyclopentadienes: High Stereoselectivity and Enantioselectivity
作者:Ching‐Nung Chen、Wei‐Min Cheng、Jian‐Kai Wang、Tzu‐Hsuan Chao、Mu‐Jeng Cheng、Rai‐Shung Liu
DOI:10.1002/anie.202012611
日期:2021.2.23
This work reports gold‐catalyzed [3+2]‐annulations of α‐diazo ketones with highly substituted cyclopentadienes, affording bicyclic 2,3‐dihydrofurans with high regio‐ and stereoselectivity. The reactions highlights the first success of tetrasubstituted alkenes to undergo [3+2]‐annulations with α‐diazo carbonyls. The enantioselective annulations are also achieved with high enantioselectivity using chiral
Propylene Polymerization with Unbridged Metallocenes: Ligand Effects on the Selectivity for Elastomeric Polypropylene
作者:Jennifer L. Maciejewski Petoff、Michael D. Bruce、Robert M. Waymouth、Athar Masood、Tapan K. Lal、Roger W. Quan、Steven J. Behrend
DOI:10.1021/om9706119
日期:1997.12.1
elastomeric polypropylene with a stereoblock microstructure. In an effort to experimentally explore the importance of the 2-arylindene ligand in producing these materials, a series of catalysts was investigated that differed significantly from the parent ligand architecture. In particular, we sought to examine the influence of ligand aryl stacking on the polymerization behavior of these metallocenes. We discovered
Gold(I)-Catalyzed Highly Enantioselective [4 + 2]-Annulations of Cyclopentadienes with Nitrosoarenes via Nitroso-Povarov versus Oxidative Nitroso-Povarov Reactions
作者:Prakash D. Jadhav、Jia-Xuan Chen、Rai-Shung Liu
DOI:10.1021/acscatal.0c01293
日期:2020.5.15
gold-catalyzed highlyenantioselective nitroso-Povarov reactions between cyclopentadienes and nitrosoarenes in cold dichloroethane, in which nitrosoarenes serve as 4π-electron donors and cyclopentadienes as 2π-donors. High enantioselectivity has been achieved for substrates over a wide scope. With the same chiral catalyst, nitroso-4-fluorobenzenes in these reactions under DCM/THF/water/air led to oxidative nitroso-Povarov
Gold(I)-Catalyzed Highly Diastereo- and Enantioselective Constructions of Bicyclo[3.2.1]oct-6-ene Frameworks via (4 + 3)-Cycloadditions
作者:Sudhakar Dattatray Tanpure、Tung-Chun Kuo、Mu-Jeng Cheng、Rai-Shung Liu
DOI:10.1021/acscatal.1c04483
日期:2022.1.7
1]oct-6-ene frameworks involves gold-catalyzed (4 + 3)-cycloadditions between 2-(1-alkynyl)-2-alken-1-ones and substituted cyclopentadienes; diastereoselectivity (dr >25:1) and enantioselectivity (up to 99.9% ee) are achieved with a chiral gold catalyst. Our DFT calculations suggest a three-step ionic mechanism for the cycloadditions of gold-containing 1,3-dipoles with cyclopentadienes, in which an exo-spatial