Functionalized olefin cross-coupling to construct carbon–carbon bonds
作者:Julian C. Lo、Jinghan Gui、Yuki Yabe、Chung-Mao Pan、Phil S. Baran
DOI:10.1038/nature14006
日期:2014.12.18
Carbonâcarbon (CâC) bonds form the backbone of many important molecules, including polymers, dyes and pharmaceutical agents. The development of new methods to create these essential connections in a rapid and practical fashion has been the focus of numerous organic chemists. This endeavour relies heavily on the ability to form CâC bonds in the presence of sensitive functional groups and congested structural environments. Here we report a chemical transformation that allows the facile construction of highly substituted and uniquely functionalized CâC bonds. Using a simple iron catalyst, an inexpensive silane and a benign solvent under ambient atmosphere, heteroatom-substituted olefins are easily reacted with electron-deficient olefins to create molecular architectures that were previously difficult or impossible to access. More than 60 examples are presented with a wide array of substrates, demonstrating the chemoselectivity and mildness of this simple reaction. Highly substituted carbonâcarbon bonds are constructed using a simple iron catalyst and an inexpensive silane: more than 60 examples of this reaction â in which heteroatom-substituted olefins are reacted with electron-deficient olefins â are presented. This paper reports the development of a new type of carbonâcarbon bond forming reaction that allows for the simple construction of molecules that were previously either impossible or laborious to access. The procedure exploits an interaction between heteroatom-substituted olefins and electron-deficient olefins to construct highly substituted carbonâcarbon bonds using a simple iron catalyst and an inexpensive silane. The authors present than sixty examples of this reaction, covering a broad range of substrates. This reaction is of relevance to the design of organic compounds including polymers, dyes, and pharmaceutical agents and semiconductors.
An efficient catalytic (2 + 2)-cycloaddition reaction leading to the formation of cyclobutane rings has been devised. The process transforms silyl enol ethers and α,β-unsaturated esters into polysubstituted cyclobutanes with a high degree of trans-stereoselectivity. Both the rate and stereoselectivity of the process can be controlled by the choice of the ester group and silyl substituents. The results
common strategy in drug development. We demonstrate a synthesis that installs a small carbocyclic ring as a structurally-rigid unit in drug lead compounds. Both trans- and cis-cyclobutane rings were constructed in excellent selectivities by controlling the reaction temperature of an EtAlCl2-catalyzed [2+2] cycloaddition between a silyl enolether and an α,β-unsaturated ester. Spirocyclopropane rings