(E)-4-oxo-β-ionone (3), (E)-4-oxo-β-irone (4), and the five-membered ring analogs 36–41 were synthesized by a novel, convergent route starting from 2-methylfuran (1). A recently discovered, intramolecular reaction of 2-(diazoacyl)furans, catalyzed by dirhodium tetraacetate, leading to dienediones served as key step, thereby testing its utility in natural-product synthesis for the first time.
                                    (E)-5-脱甲基-4-氧代-
β-紫罗兰酮(2),(E)-4-氧代-
β-紫罗兰酮(3),(E)-4-氧代-
β-紫罗兰酮(4)和五元环类似物36 – 41是通过新颖的,收敛的路线从
2-甲基呋喃(1)合成的。最近发现的,由
四乙酸二
乙酸钠催化的2-(重氮酰基)
呋喃的分子内反应是导致二烯键的关键步骤,从而首次测试了其在
天然产物合成中的效用。