Rh-Catalyzed Cyclization of 3-Aryloxycarbonyldiazonaphthoquinones for the Synthesis of β-Phenylnaphthalene Lactones and Formal Synthesis of Pradimicinone
In this study, we developed a novel method for the synthesis of beta-phenylnaphthalene lactones. The diazo-transfer reactions of 2-azido-1,3-dimethylimidazolinium chlorides to 3-aryloxycarbonyl-1-naphthols proceeded smoothly to give corresponding 3-aryloxycarbonyldiazonaphthoquinones in high yields. These intermediates were further transformed to beta-phenylnaphthalene lactones through a Rh-catalyzed intramolecular formal C-H insertion reaction. This method of lactone formation was efficiently applied to the formal total synthesis of pradimicinone.
A New Route to Hydrophenanthrene Ring System Involving Aryl Participated Intramolecular Cyclisation of Diazomethyl Ketones
Abstract The tricyclic enones 4 and 5 have been synthesised involving acid catalysed intramolecular cyclisation of the diazo-methyl ketones 1 and 2 respectively. The present synthesis constitutes a new route to hydrophenanthrene ring system.