‘High-Surface Sodium’ as a Reducing Agent for TiCl3
作者:Alois Fürstner、Günter Seidel
DOI:10.1055/s-1995-3854
日期:1995.1
Sodium deposited on inorganic supports such as Al2O3, TiO2 and NaCl (‘high-surface sodium’) is a cheap, readily prepared, nonpyrophoric reducing agent for TiCl3. The low-valent titanium thus obtained, after only 1 h reduction time, is well suited for McMurry coupling reactions, particularly of aromatic carbonyl compounds. It exhibits a previously unrivalled template effect for the cyclization of dicarbonyl compounds to (macrocyclic) cycloalkenes and is suitable for the reduction of N-acyl-2-aminobenzophenone derivatives to 2,3-disubstituted indoles. Even a 36-membered ring could be formed without recourse to high dilution techniques.
Alkali metal ion mediated cyclization of 4,4′-(3,6-dioxaocta-1,8-diyloxy)-bis(benzophenone)
作者:Mark D. Ferguson、Jared A. Butcher
DOI:10.1016/s0040-4039(00)79209-4
日期:1993.6
The effect of alkali metal ions on the ratio of cyclization to polymer formation was investigated. The presence of potassium ions enhances the formation of macrocycles, while lithium ions suppress the reaction.