Synthesis of Tetrahydrofuro[2,3-b][1]benzopyranones by the Ring-Expansion Reaction of Methanochromanone with Symmetric Ketones
摘要:
In the presence of SnCl4, 2,3-dimethoxycarbonylmethanochromanone (8) was transformed into a zwitterion which easily reacted with symmetric ketones to give the tetrahydrofuro[2,3-b][1]benzopyranone derivatives in good yields with high diastereoselectivity.