A Flow Microreactor System Enables Organolithium Reactions without Protecting Alkoxycarbonyl Groups
作者:Aiichiro Nagaki、Heejin Kim、Yuya Moriwaki、Chika Matsuo、Jun-ichi Yoshida
DOI:10.1002/chem.201000876
日期:——
A flowmicroreactor system consisting of micromixers and microtube reactors provides an effective tool for the generation and reactions of aryllithiums bearing an alkoxycarbonyl group at para‐, meta‐, and ortho‐positions. Alkyl p‐ and m‐lithiobenzoates were generated by the I/Li exchange reaction with PhLi. The Br/Li exchange reactions with sBuLi were unsuccessful. Subsequent reactions of the resulting
Structurally diverse arylchlorides were silylated with sodium silylsilanolate reagents in the presence of a Ni(cod)2 catalyst complexed with a phosphine ligand; PMe2Ph for electron-rich substrates, and PCy2Ph for electron-deficient ones. The mild reaction conditions allowed the silylation of various arylchlorides including functionalised drug molecules.
A rhodium-catalyzed silylation reaction of carbon-cyano bonds using disilane has been developed. Under these catalytic conditions, carbon-cyano bonds in aryl, alkenyl, allyl, and benzyl cyanides bearing a variety of functional groups can be silylated. The observation of an enamine side product in the silylation of benzyl cyanides and related stoichiometric studies indicate that the carbon-cyano bond cleavage proceeds through the deinsertion of silyl isocyanide from eta(2)-iminoacyl complex B. Knowledge gained from these studies has led to the development of a new intramolecular biaryl coupling reaction in which aryl cyanides and aryl chlorides are cross-coupled.
Rh(I)-Catalyzed Silylation of Aryl and Alkenyl Cyanides Involving the Cleavage of C−C and Si−Si Bonds
作者:Mamoru Tobisu、Yusuke Kita、Naoto Chatani
DOI:10.1021/ja062745w
日期:2006.6.1
The Rh(I)-catalyzed silylation of nitriles with disilanes is described. The cleavage of inert carbon-cyano and silicon-silicon bonds occurs in this catalysis.