Anti-selective and regioselective aldol addition of ketones with aldehydes using MgI2 as promoter
作者:Han-Xun Wei、Richard L. Jasoni、Huawu Shao、Jiali Hu、Paul W. Paré
DOI:10.1016/j.tet.2004.09.098
日期:2004.12
The firstexample of a direct aldehyde–ketone coupling using the secondary amine piperidine as base in the presence of MgI2 to generate high selectivity of anti-aldol products from unmodified ethyl ketones in high yield is reported. The coupling reactions were carried out in a one-pot reaction by mixing four reaction components at room temperature. In the case of unsymmetrical ketones, addition was
A mild method for the diastereoselectiveMukaiyamaaldolreaction is reported. By using a lowloading of the gallium(III) triflatecatalyst (down to 0.01 mol-%), the transformation proceeds efficiently to afford the corresponding β-hydroxy ketones in yields up to 92 %. To the best of our knowledge, this is the first report of a metal triflate acting as a safe, bench-stable, and slow-releasing source
Aldolreactionsbetweenaldehydes and trimethylsilylenolate; generated from ketones or thioesters proceeded smoothly in the presence of a Lewis base catalyst such as tetrabutylammonium phenoxide or p-methoxyphenoxide in THF to afford the corresponding aldols in high yields with high syn-selectivity.
Highly Diastereoselective Reformatsky-Type Reaction Promoted by Tin Iodide Ate Complex
作者:Ikuya Shibata、Toshihiro Suwa、Hideaki Sakakibara、Akio Baba
DOI:10.1021/ol0171214
日期:2002.1.1
GRAPHICSAn ate type of tin complex, Li+[n-Bu2SnI3](-)/HMPA, works as a novel type of reagent to accomplish the highly diastereoselective Reformatsky-type reaction by the halogen-metal exchange method.