PALLADIUM-CATALYZED NIRG EXPANSION OF HYDROXY METHOX YALLENYLPHTHALANS AS A NOVEL SYNTHETIC METHOD FOR HIGHLY SUBSTITUTED 4-ISOCHROMANONE DERIVATIVES

摘要

The palladium(0)-catalyzed ring expansion reaction using hydroxy methoxyallenylphthalans (3) proceeded smoothly to give highly substituted 4-isochromanone derivatives (4),and treatment of commercialy available phthalide (5) with lithium methoxyallene furnished two atom ring-expanded endobenzoxepin-5-one(8).