Novel Short-Step Synthesis of Functionalized γ-Phenyl-β-hydroxybutenoates and their Cyclization to 4-Hydroxycoumarins via the <i>N</i>-Hydroxybenzotriazole Methodology
A novel method for the synthesis of functionalized 3- substituted 4-hydroxycoumarins is reported. C-Acylation com- pounds were derived from the reaction of the N-hydroxybenzotri- azole ester of the functionalized acetyl salicylic acids and a variety of active methylene compounds and cyclized to the title com- pounds. The synthesis is simple and the compounds are produced in yields varying from 39 to
A Rh(<scp>iii</scp>)-catalyzed cascade C–H functionalization/cyclization reaction of salicylaldehydes with diazomalonates for the synthesis of 4-hydroxycoumarin derivatives
作者:Guo-Dong Xu、Zhi-Zhen Huang
DOI:10.1039/c8nj04576c
日期:——
A cascadeC–H functionalization/cyclization reaction of salicylaldehydes with α-diazomalonates has been developed for the synthesis of 4-hydroxycoumarin derivatives under the catalysis of rhodium(III) and in the presence of acetic acid. A plausible mechanism involving aldehydic C(sp2)–H activation by rhodium(III) and rhodium(III) catalyzed carbene insertion is also proposed.