Reaction of in-situ generated α-silylated allylic phosphonate carbanions with aldehydes. An unexpected cyclization reaction
作者:Hashim Al-Badri、Elie About-Jaudet、Noël Collignon
DOI:10.1039/p19960000931
日期:——
Lithiated α-trimethylsilyl cinnamyl-, prenyl- and crotyl-phosphonate carbanions 4 were generated quantitatively in situ from corresponding phosphonates 1, and their reactions with aldehydes were studied. When reacted at 0 °C with aromatic or aliphatic aldehydes, the cinnamyl derivative 4a gave phosphonodienes 7 in high yield and with high stereoselectivity. In contrast, the prenyl derivative 4b showed
原位定量生成锂化的α-三甲基甲硅烷基肉桂酸,异戊二烯基和巴豆基膦酸酯碳负离子4由相应的膦酸酯1得到,并研究了它们与醛的反应。当在0℃下与芳族或脂族醛反应时,肉桂基衍生物4a以高收率和高立体选择性产生膦二烯7。相反,异戊二烯基衍生物4b在与芳族醛的反应中显示出严格的γ-区域选择性,从而导致环状有机磷化合物11;用脂族醛,得到相应的杂环化合物11作为主要产物和膦二烯9的作为次要产物的混合物。巴豆基衍生物4c与芳香族或脂肪族醛的反应也具有很高的γ-区域选择性,在–70°C水解时可以分离出膦醇13。当加热至接近50°C时,醇盐12进行环化反应,得到杂环化合物14。