Intermolecular cycloaddition reaction of unactivated alkenes and o-quinone methides generated by electrochemical oxidation: a proposed biomimetic approach to the euglobal skeletons
作者:Kazuhiro Chiba、Junko Sonoyama、Masahiro Tada
DOI:10.1039/c39950001381
日期:——
Electrochemical oxidation of o-[1-(phenylthio)alkyl]phenois in lithium perchlorate–nitroalkane gives corresponding o-quinone methides, which are trapped by unactivated alkenes to form chromanes including euglobal skeletons.
Electrochemical synthesis of chroman and euglobal skeletons via cycloaddition reaction of o-quinone methides and alkenes
作者:Kazuhiro Chiba、Junko Sonoyama、Masahiro Tada
DOI:10.1039/p19960001435
日期:——
synthesized by the intermolecular cycloaddition reaction of terpenes and o-quinone methides generated in situ by electrochemical oxidation. In a two-phase reaction medium composed of hexane-lithium perchlorate/nitromethane, 2-[1-(propylsulfanyl)alkyl]phenols were selectively oxidized to give the corresponding unstable o-quinone methides. These intermediates were trapped in situ by unactivated alkenes or easily
Synthesis of chromans by photosensitized electrochemical oxidation of sulfides mediated by methylene blue
作者:Kazuhiro Chiba、Yoshihiro Yamaguchi、Masahiro Tada
DOI:10.1016/s0040-4039(98)02048-6
日期:1998.12
o-Quinone methides were generated by a photosensitized cleavage of sulfides under neutral conditions using visible light provided by a 100 Watt spot light and methylene blue as a sensitizer. The key step in the oxidative cleavage is the transfer of one electron form the sulfide to the electronically excited visible dye. The resulting phenylthio radical cation undergoes frangmentation, and the correspondign