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)
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-sigmatropichydrogenshift 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.
Efficient syntheses of phosphonylated isochromenes by regioselective 6-endo-dig addition to carbon-carbon triple bond catalyzed by Pd(OAc)2
作者:Fei Wang、Zhiwei Miao、Ruyu Chen
DOI:10.1039/b908313h
日期:——
Palladium(II)-catalyzed cycloisomerization of [(2-alkynylphenyl)hydroxymethyl]phosphonates 6 provides an efficient route to phosphonylated isochromenes 7 in THF at room temperature and the reaction proceeded in a regioselective manner leading to the 6-endo-dig products 7 in moderate to excellent yields.