A novel Pd(II)-catalyzed dehydrogenative cross-coupling reaction between coumarins and H-phosphonates has been developed to give the corresponding 3-phosphonated products in moderate to good yields with high selectivity.
A comparative study of the interaction of salicylaldehydes with phosphonoacetates under Knoevenagel reaction conditions. Synthesis of 1,2-benzoxaphosphorines and their dimers
作者:Anka Bojilova、R. Nikolova、Christo Ivanov、Nestor A. Rodios、A. Terzis、C.P. Raptopoulou
DOI:10.1016/0040-4020(96)00748-x
日期:1996.9
The reaction of salicylaldehydes 5 with phosphonoacetates 6 gives the coumarin-3-phosphonates 7 and the 1,2-benzoxaphosphorine-3-carboxylates 8 in yields and 7:8 ratios depending on the reaction conditions. A mechanistic explanation is given for the stereoselectivity of these reactions. Irradiation of compounds 8 or direct exposure to sunlight causes their head-to-tail dimerization, giving the dimers
AgNO3-catalyzed direct C-sp2-H radical phosphorylation of coumarins with H-phosphites to afford selective coumarin-3-yl phosphonate in moderate to good yields is described. This method can be also applied to the phosphorylation of quinolinones. (C) 2015 Elsevier Ltd. All rights reserved.
Catalytic activity of chelating N-heterocyclic carbene palladium complexes towards selective phosphorylation of coumarins
作者:Liangru Yang、Xinchi Zhang、Jinwei Yuan、Yongmei Xiao、Pu Mao
DOI:10.1016/j.jorganchem.2016.06.015
日期:2016.9
The catalyticactivity of a series of heteroaryl coordinated chelating N-heterocyclic carbene (NHC) palladium complexes bearing different N-substituents, NHC backbones and chelating rings towards the phosphorylation of coumarins, and the relationship between the activity and the structure are presented. The results showed that the chelating NHC palladium complex Ia–b bearing the most σ-donating backbone
A new method for faster and simple preparation of 3,3',4,4'-tetrahydro-3,3'-disubstituted-4,4'-biscoumarins with participation of an organozinc reagent is reported. The reaction is promoted by ultrasound irradiation and it offers a simple experimental setup and excellent reproducibility of the results. Moreover, homodimers were isolated in yields of 45⁻92%. The dimerization conditions are applicable