Efficient Synthesis of Alkynylsilyl Ethers and Silaketals via Base-Induced Alkynylsilane Alcoholysis
作者:Jonathan B. Grimm、Daesung Lee
DOI:10.1021/jo048908l
日期:2004.12.1
The efficient silylation of alcohols with di- and trialkynylsilanes was achieved under base-catalyzed conditions to afford alkynyl silyl ethers and symmetrical alkynyl silaketals in good yield. A selective alcoholysis of dialkynyl silyl ethers to mixed silaketals was also demonstrated. These products served as substrates for enyne ring-closing metathesis and, consequently, as precursors to stereochemically defined 1,3-dienes.
Group-Selective Ring-Closing Enyne Metathesis: Concentration-Dependent Selectivity Profile of Alkynylsilyloxy-Tethered Dienynes
作者:Sarah V. Maifeld、Reagan L. Miller、Daesung Lee
DOI:10.1021/ja046043n
日期:2004.10.1
Grubbs first- and second-generation catalyst. The remarkable selectivity increase at higher concentration for differentiating between two alkene moieties in nearly identical steric and stereoelectronic environments is believed to be the result of a higher ring-closure rate for smaller-sized ring formation under rapid pre-equilibration of the two alkylidene species generated from either alkene moiety.