Efficient Syntheses of (Thio)phosphonylated Isobenzofurans by Tandem Nucleophilic Addition and Regioselective 5-exo-dig Addition to Carbon-Carbon Triple Bond: Cooperative Effect to 1,8-Diazabicyclo[5.4.0]undec-7-ene (DBU)
作者:Fei Wang、Yadan Wang、Lingchao Cai、Zhiwei Miao、Ruyu Chen
DOI:10.1002/adsc.200800484
日期:——
in THF at room temperature. In all cases, the reaction proceeded in a regioselective manner leading to the 5-exo-dig products 3 in excellent yields. The phenomenon of a 1,5-sigmatropic hydrogen shift or a 1,5-sigmatropic methyl shift was observed in this reaction depending on the different substituent groups such as R3 in the o-alkynylbenzaldehyde or o-alkynylacetophenone 2 substrates.
的串联亲核加成环化反应ö -alkynylbenzaldehydes或ö -alkynylacetophenones 2与二烷基磷酸酯或二烷基硫代磷酸酯1发生非常顺利在1,8-二氮杂双环[5.4.0]十一碳-7-烯(DBU)的存在下在室温下为THF。在所有情况下,反应都以区域选择性的方式进行,从而以优异的产率产生了5 -exo-dig产物3。在该反应中观察到1,5-σ移位氢移或1,5-σ迁移甲基移现象取决于不同取代基例如R 3在Ò -alkynylbenzaldehyde或ö-炔基苯乙酮2种底物。