Rhodium(III)-Catalyzed C–H Activation/Annulation with Vinyl Esters as an Acetylene Equivalent
作者:Nicola J. Webb、Stephen P. Marsden、Steven A. Raw
DOI:10.1021/ol502095z
日期:2014.9.19
The behavior of electron-richalkenes in rhodium-catalyzed C–H activation/annulation reactions is investigated. Vinyl acetate emerges as a convenient acetylene equivalent, facilitating the synthesis of sixteen 3,4-unsubstituted isoquinolones, as well as select heteroaryl-fused pyridones. The complementary regiochemical preferences of enol ethers versus enol esters/enamides is discussed.
An efficient synthesis of 2,5-disubstitutedoxazolesvia Co(III) catalysis is described herein. The synthesis is achieved under mild conditions through [3+2] cycloaddition of N-pivaloyloxyamides and alkynes. The reaction operates through an internal oxidation pathway and features a very broad substrate scope. The one-step synthesis of natural products such as texamine and balsoxin has been demonstrated
[4+2] or [4+1] Annulation: Changing the Reaction Pathway of a Rhodium-Catalyzed Process by Tuning the Cp Ligand
作者:Seung Youn Hong、Jisu Jeong、Sukbok Chang
DOI:10.1002/anie.201612559
日期:2017.2.20
A change in reaction pathway was achieved for the first time by tuning the cyclopentadienyl (Cp) ligand used for the rhodium‐catalyzed cyclization of benzamides with conjugated enynones. Depending on the Cp ligand, the reaction pathway switched between [4+2] and [4+1] annulation. Electronic effects turned out to be crucial for the product distribution. The dichotomy was attributed to the alteration
Rhodium(III)-Catalyzed C–H Activation: Ligand-Controlled Regioselective Synthesis of 4-Methyl-Substituted Dihydroisoquinolones
作者:Joyann S. Barber、Stephanie Scales、Michelle Tran-Dubé、Fen Wang、Neal W. Sach、Louise Bernier、Michael R. Collins、JinJiang Zhu、Indrawan J. McAlpine、Ryan L. Patman
DOI:10.1021/acs.orglett.9b02029
日期:2019.7.19
Rh-catalyzed C–H functionalization of O-pivaloyl benzhydroxamic acids with propene gas provides access to 4-methyl-substituted dihydroisoquinolones. Good to excellent levels of regioselectivity are achieved using [CptRhCl2]2 as a precatalyst under optimized conditions. Thorough examination of aryl/heteroaryl O-pivaloyl hydroxamic acid substrates, ligand effects on C–Hsiteselectivity, alkene scope
Rh催化O-新戊酰基苯氧肟酸的C–H官能团与丙烯气体的接触提供了被4-甲基取代的二氢异喹诺酮类化合物的途径。在优化的条件下,使用[Cp t RhCl 2 ] 2作为预催化剂,可以实现良好至优异的区域选择性。全面讨论了芳基/杂芳基O-新戊基异羟肟酸底物的检测,配体对C–H位置选择性,烯烃范围和规模证明的影响。
Rh(III)- and Ir(III)-Catalyzed C–H Alkynylation of Arenes under Chelation Assistance
作者:Fang Xie、Zisong Qi、Songjie Yu、Xingwei Li
DOI:10.1021/ja501910e
日期:2014.3.26
Rh(III)- and Ir(III)-catalyzed, chelation-assisted C-H alkynylation of a broad scope of (hetero)arenes has been developed using hypervalent iodine-alkyne reagents. Heterocycles, N-methoxy imines, azomethine imines, secondary carboxamides, azo compounds, N-nitrosoamines, and nitrones are viable directing groups to entail ortho C-H alkynylation. The reaction proceeded under mild conditions and with controllable