Diastereoselective Coupling of 1,3-Diene, Ketone, and Organometallic Reagents by Nickel Catalyst: Stereoselective Construction of Tetrasubstituted Carbon Centers
Intramolecular nucleophilic attack at silicon in o-silylbenzyl alcohols. Generation of allyl and benzyl anion equivalents
摘要:
Substituted silyl ethers of o-bromobenzyl alcohols and the derived o-silylbenzyl alcohols were used to transfer allyl and benzyl groups from silicon to the electrophiles benzaldehyde and benzophenone in excellent yields. gamma-Oxidosilane intermediates (and possibly hypercoordinated silicon intermediates) are postulated. (C) 2011 Elsevier Ltd. All rights reserved.
Silicon-Based Cross-Coupling Reagent and Production Method of Organic Compound Using the Same
申请人:Nakao Yoshiaki
公开号:US20090069577A1
公开(公告)日:2009-03-12
In one embodiment of the present invention, a silicon-based cross-coupling reagent is disclosed which is a highly stable tetraorganosilicon compound allowing for a cross-coupling reaction under mild reaction conditions without using fluoride ions, transition metal promoter, or strong bases, and the residue of the silicon reagent can be recovered and reused. The silicon-based cross-coupling reagent is a silicon compound in which an o-hydroxymethylphenyl group is connected to a silicon atom for intramolecular activation.
Synthesis of Biaryls and Oligoarenes Using Aryl[2-(hydroxymethyl)phenyl]dimethylsilanes
作者:Jinshui Chen、Masaaki Tanaka、Akhila K. Sahoo、Masahide Takeda、Akira Yada、Yoshiaki Nakao、Tamejiro Hiyama
DOI:10.1246/bcsj.20090325
日期:2010.5.15
Through intramolecular activation, highly stable aryl[2-(hydroxymethyl)phenyl]dimethylsilanes can selectively transfer their aryl groups to effect a cross-coupling reaction with various aryl bromides and chlorides in the presence of a weak non-fluoride base and a palladium/copper catalyst. This reaction tolerates a wide range of functional groups, producing the corresponding functionalized biaryls in high yields with excellent chemoselectivity. Newly disclosed reaction conditions allow the recovery of a cyclic silyl ether in modest-to-good yields and reuse for the synthesis of the arylsilanes. The introduction of two isopropyl groups on the silicon center instead of methyl groups improves the stability and allows quantitative recovery of the silicon residue. Finally, aryl halides having an O-protected [2-(hydroxymethyl)phenyl]dimethylsilyl group cross-couple with the arylsilane reagents to give silyl-functionalized biaryls. Upon deprotection, the biaryls further react with the silylated electrophiles. The iterative cross-coupling–deprotection sequences allow rapid assembly of silylated oligoarenes. Syntheses of di- and trisilyloligoarenes are also achieved by use of orthogonal O-protecting groups.
achievement of the corresponding enantioselective transformations using the tetraorganosilicon reagents, providing the silicon-based approach to opticallyactiveketones and substituted piperidones that serve as synthetic intermediates of pharmaceuticals. A rhodium alkoxide species is suggested to be responsible for a transmetalation step on the basis of the observed kinetic resolution of a racemic chiral phenylsilane
A method for the carboallylation of electron-deficient alkenes with tetraorganosilicon reagents and allylic carbonates based on Pd/Cu catalysis has been developed. This method affords a wide range of structurally diverse carbon skeletons from readily available starting materials, and tolerates various functional groups.
Copper-catalyzed Carboxylation of Unactivated Aryl- and Alkenylsilanes with Carbon Dioxide
作者:Woo-Jin Yoo、Junpei Kondo、Shū Kobayashi
DOI:10.1246/cl.190577
日期:2019.10.5
A mild synthetic protocol for the preparation of aryl and alkenyl carboxylic acids was developed through a copper-catalyzedcarboxylation reaction of organosilanes with carbondioxide. The key to t...