Tandem Intramolecular Silylformylation and Silicon-Assisted Cross-Coupling Reactions. Synthesis of Geometrically Defined α,β-Unsaturated Aldehydes
作者:Scott E. Denmark、Tetsuya Kobayashi
DOI:10.1021/jo034064e
日期:2003.6.1
The palladium- and copper-catalyzed cross-coupling reactions of cyclic silyl ethers with aryl iodides are reported. Silyl ethers 3 were readily prepared by intramolecular silylformylation of homopropargyl silyl ethers 2 under a carbon monoxide atmosphere. The reaction of cyclic silyl ethers 3with various aryl iodides 7 in the presence of [(allyl)PdCl](2), CuI, a hydrosilane, and KF.2H(2)O in DMF at
报道了环甲硅烷基醚与芳基碘化物的钯和铜催化的交叉偶联反应。在一氧化碳气氛下,通过使炔丙基甲硅烷基醚2进行分子内甲硅烷基甲酰化,可以容易地制备甲硅烷基醚3。在[(烯丙基)PdCl](2),CuI,氢硅烷和KF.2H(2)O存在下,室温下,环状甲硅烷基醚3与各种芳基碘化物7在DMF中于室温反应,得到不饱和的α,β。醛偶联产物8的收率很高。在此过程中对铜的需求表明,从硅到铜的金属转移是该机理中的重要一步。尽管硅氧烷3和产物8在碱性条件下不稳定,但KF.2H(2)O提供了对硅的反应性和降低的碱度的适当平衡。