Deconstruction as a Strategy for the Design of Libraries of Self-Assembling Dendrons
作者:Brad M. Rosen、Mihai Peterca、Chenghong Huang、Xiangbing Zeng、Goran Ungar、Virgil Percec
DOI:10.1002/anie.201002514
日期:2010.9.17
Bringing down the dendron: The deconstruction of self‐assembling dendrons represents a new strategy for the rational design of libraries of self‐assembling dendrons with unprecedented primary structure (see picture). In this strategy, molecular targets are designed by systematically removing branches from a parent dendron. This approach provides a diversity of molecular topologies unencountered in
Two-Step, One-Pot Ni-Catalyzed Neopentylglycolborylation and Complementary Pd/Ni-Catalyzed Cross-Coupling with Aryl Halides, Mesylates, and Tosylates
作者:Daniela A. Wilson、Christopher J. Wilson、Brad M. Rosen、Virgil Percec
DOI:10.1021/ol801972f
日期:2008.11.6
Two-step, one-pot neopentylglycolborylation of aryl iodides and bromides catalyzed by NiCl2(dppe) and NiCl2(dppp) is reported. Electron-rich and electron-deficient aryl neopentylglycolboronates were efficiently cross-coupled with aryl iodides, bromides, chlorides, mesylates, and tosylates by exploiting complementary Pd/Ni and Ni/Ni catalysis. The borylation route was further extended to a three-step
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.
Sequential Ni-Catalyzed Borylation and Cross-Coupling of Aryl Halides via in Situ Prepared Neopentylglycolborane
作者:Brad M. Rosen、Chenghong Huang、Virgil Percec
DOI:10.1021/ol800832n
日期:2008.6.1
A procedure for NiCl2(dppp)-catalyzed pinacolborylation and neopentylglycolborylation that utilizes in situ prepared inexpensive pinacolborane and neopentylglycolborane is reported. The scope of this reaction was demonstrated with a variety of aryl bromides and iodides. The resulting aryl neopentylglycolboronic esters undergo a NiCl2(dppe)-catalyzed cross-coupling with aryl halides, resulting in an extremely effici cost-effective method for the synthesis of functional biaryls, dendritic building blocks, and other complex architectures.
[EN] PROCESSES FOR THE PREPARATION OF BIPHENYL COMPOUNDS<br/>[FR] PROCÉDÉS POUR LA FABRICATION DE COMPOSÉS BIPHÉNYLES