A facile access to spiro furanone skeleton based on Pd(II)-mediated cyclization-carbonylation of propargylic esters |
| |
Authors: | Keisuke Kato Hideaki Nouchi Satoshi Takaishi Hikaru Tanaka Tomoyuki Mochida Koki Shigenobu |
| |
Institution: | a Faculty of Pharmaceutical Sciences, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan b Department of Chemistry, Faculty of Science, Toho University, 2-2-1 Miyama, Funabashi, Chiba 274-8510, Japan |
| |
Abstract: | The oxidative cyclization-carbonylation of propargylic esters mediated by Pd(II) afforded cyclic orthoesters, which were hydrolyzed into γ-acetoxy-β-ketoesters. Based on the NMR experiments, it was presumed that the cyclization reaction was initiated by a nucleophilic attack of carbonyl oxygen to the alkyne carbon coordinated to palladium(II). When the γ-acetoxy-β-ketoesters were treated with a basic condition, Knoevenagel-Claisen type condensation took place, and spiro furanone derivatives were obtained in good yields. We applied these reactions to steroid derivatives, and steroid derivatives having a spiro furanone fragment were synthesized. Among them, the spiro furanone 4j had vasorelaxant and bradycardiac activities. Compounds 2i-4k had inhibitory effect on CYP3A. |
| |
Keywords: | Palladium Orthoester Cyclization-carbonylation Propargylic ester β-Ketoesters Spiro furanone 3(2H)-Furanone Ethisterone Mestranol Ethynylestradiol |
本文献已被 ScienceDirect 等数据库收录! |
|