Palladium(II) Acetate Catalyzed Cyclization–Coupling of (o-Ethynylphenyl)phosphonic Acid Monoesters with Allyl Halides
作者:Zecai Xiao、Ai-Yun Peng
DOI:10.1055/s-0039-1689936
日期:2019.9
Pd(OAc)2-catalyzed tandem cyclization–coupling reaction of (o-ethynylphenyl)phosphonicacid monoesters and allyl halides has been developed. This reaction provides an efficient, mild, general and regioselective way to synthesize 4-allylphosphaisocoumarins. A Pd(OAc)2-catalyzed tandem cyclization–coupling reaction of (o-ethynylphenyl)phosphonicacid monoesters and allyl halides has been developed. This reaction
In this work, we found that acids (i.e., HCl and NaHSO3) rather than bases could catalyze the cyclization of o-alkynylphenylphosphonicacidmonoesters at slow rates and give phosphaisocoumarins in low to medium yields, whereas the cyclization of (o-hydroxyphenyl)ethynylphosphinates proceeded very smoothly under basic conditions rather than acidic conditions, and a series of phosphachromones could be
4-bromophosphaisocoumarins underwent a dehalogenation–alcoholysis tandem reaction. The possible mechanism for the alcoholysis reaction was discussed. In addition, direct access to 2-(2-oxoalkyl)phenylphosphonates was developed by the mercury(II)-catalyzed hydration of 2-(1-alkynly)phenylphosphonates with high regioselectivity. In a preliminary study, the obtained novel keto phosphonates showed medium inhibitory