Synthesis of Coumarins, 4-Hydroxycoumarins, and 4-Hydroxyquinolinones by Tellurium-Triggered Cyclizations<sup>1</sup>
作者:Donald C. Dittmer、Qun Li、Dimitry V. Avilov
DOI:10.1021/jo050070u
日期:2005.6.1
can be conveniently prepared by treatment of α-halocarboxylic acid esters of salicylaldehyde, o-hydroxyacetophenone, methylsalicylate, and methyl N-methyl- or N-phenylanthranilates with sodium or lithium telluride. Phenylketene formation competes with cyclization of the α-chlorophenylacetate ester of methylsalicylate as demonstrated by a trapping experiment with benzylamine. Elemental tellurium