Ni(COD)2/PCy3 Catalyzed Cross-Coupling of Aryl and Heteroaryl Neopentylglycolboronates with Aryl and Heteroaryl Mesylates and Sulfamates in THF at Room Temperature
摘要:
Reaction conditions for the Ni(COD)(2)/PCy3 catalyzed cross-coupling of aryl neopentylglycolboronates with aryl mesylates were developed. By using optimized reaction conditions, Ni(COD)(2)/PCy3 was shown to be a versatile catalyst for the cross-coupling of a diversity of aryl neopentylglycolboronates with aryl and heteroaryl mesylates and sulfamates containing both electron-donating and electron-withdrawing substituents in their para, ortho, and meta positions in THF at room temperature. This Ni-catalyzed cross-coupling of aryl neopentylglycolboronates is also effective for the synthesis of heterobiaryls and biaryls containing electrophilic functionalities sensitive to organolithium and organomagnesium derivatives. In combination with the recently developed Ni-catalyzed neopentylglycolborylation, all Ni-catalyzed routes to functional biaryls and heterobiaryls are now easily accessible.
Neopentylglycolborylation of Aryl Chlorides Catalyzed by the Mixed Ligand System NiCl<sub>2</sub>(dppp)/dppf
作者:Costel Moldoveanu、Daniela A. Wilson、Christopher J. Wilson、Patrick Corcoran、Brad M. Rosen、Virgil Percec
DOI:10.1021/ol902155e
日期:2009.11.5
The mixedligandsystem 10 mol % NiCl2(dppp) with 5 mol % dppf was discovered to be an extremely efficient catalyst for the neopentylglycolborylation of a diversity of electron-rich and electron-deficient aryl chlorides. Optimization showed that 5 mol % catalyst with 10% dppf was even more efficient. These results highlight the complexity of the relationship between catalyst and coligand in Ni catalysis
The copper(I)-catalyzed carboxylation reaction of aryl- and alkenylboronic esters proceeded smoothly under CO(2) to give the corresponding carboxylic acid in good yield. This reaction showed wide generality with higher functional group tolerance compared to the corresponding Rh(I)-catalyzed reaction.
Rhodium(I)-Catalyzed Carboxylation of Aryl- and Alkenylboronic Esters with CO<sub>2</sub>
When the esters of arylboronic acids with 2,2-dimethylpropan-1,3-diol were treated with a catalytic amount of [Rh(OH)(cod)]2 in the presence of 1,3-bis(diphenylphosphino)propane and CsF in dioxane at 60 degrees C under carbon dioxide atmosphere, the benzoic acid derivatives were obtained in good yields. Reactions of alkenylboronic esters also proceeded under similar conditions to give alpha,beta-unsaturated carboxylic acids. As these boronic esters are now easily available through coupling or direct borylation reactions, this method would be a useful method for the preparation of various functionalized aryl- and alkenyl-carboxylic acids.
Ni(COD)<sub>2</sub>/PCy<sub>3</sub> Catalyzed Cross-Coupling of Aryl and Heteroaryl Neopentylglycolboronates with Aryl and Heteroaryl Mesylates and Sulfamates in THF at Room Temperature
作者:Pawaret Leowanawat、Na Zhang、Ana-Maria Resmerita、Brad M. Rosen、Virgil Percec
DOI:10.1021/jo202037x
日期:2011.12.16
Reaction conditions for the Ni(COD)(2)/PCy3 catalyzed cross-coupling of aryl neopentylglycolboronates with aryl mesylates were developed. By using optimized reaction conditions, Ni(COD)(2)/PCy3 was shown to be a versatile catalyst for the cross-coupling of a diversity of aryl neopentylglycolboronates with aryl and heteroaryl mesylates and sulfamates containing both electron-donating and electron-withdrawing substituents in their para, ortho, and meta positions in THF at room temperature. This Ni-catalyzed cross-coupling of aryl neopentylglycolboronates is also effective for the synthesis of heterobiaryls and biaryls containing electrophilic functionalities sensitive to organolithium and organomagnesium derivatives. In combination with the recently developed Ni-catalyzed neopentylglycolborylation, all Ni-catalyzed routes to functional biaryls and heterobiaryls are now easily accessible.
Zero-Valent Metals Accelerate the Neopentylglycolborylation of Aryl Halides Catalyzed by NiCl<sub>2</sub>-Based Mixed-Ligand Systems
作者:Pawaret Leowanawat、Ana-Maria Resmerita、Costel Moldoveanu、Chi Liu、Na Zhang、Daniela A. Wilson、Lisa M. Hoang、Brad M. Rosen、Virgil Percec
DOI:10.1021/jo101718v
日期:2010.11.19
The highly active mixed-ligand catalytic system NiCl2(dppp)/dppf combined with the reducing effect of zerovalent Zn and of other metals was used to demonstrate a method for the dramatic acceleration of the rate and for the enhancement of the yield of Ni-catalyzed neopentylglycolborylation of aryl halides A diversity of electron-rich and electron-deficient aryl iodides, bromides, and chlorides were efficiently neopentylglycolborylated, typically in 1 h or less This acceleration is particularly remarkable for the generally less reactive aryl bromides and chlorides and for all ortho-substituted aryl halides By accelerating the rate of borylation and reducing its reaction time to complete conversion, pathways leading to protodeborylated or hydrodehalogenated side products have a reduced impact on the outcome of the overall reaction Although Zn powder was the reducing agent of choice, compatibility of this technique with more readily recoverable Zn chips, as well as other metals such as Mn, Mg, Fe, Al, and Ca, has demonstrated the broad scope of this synthetic method