Alkynes may be easily alkylated by sequential treatment with n-BuLi followed by an alkyl halide in THF. Primary iodides give excellent yields (75-99%) as do bromides in the presence of catalytic amounts of Bu4NI or NaI; in the absence of an iodide source, bromides react poorly. This method offers advantages over existing methods which use HMPA or NH3 as co-solvents. (C) 2001 Elsevier Science Ltd. All rights reserved.
Preparation of<i>E</i>-Alkenes Using Lithium and 1,3-Diaminopropane
作者:Irena Ková[rbreve]ová、Ludvík Streinz
DOI:10.1080/00397919308011125
日期:1993.9
A new selective reducing system, lithium in 1,3-diaminopropane, is described, which enables the preparation of E-olefins from acetylenes in high purity.