Treatment of the cis-2,3-disubstituted dihydropyran-4-ones 1 with iodosobenzene diacetate and trimethylsilyl bromide or iodide afforded the α-halo dihydropyran-4-ones 2/3 in 81-93% yield. The α-iodo dihydropyran-4-one 3c was then cross-coupled under palladium(0) catalysis to furnish the α-aryl and α-vinyl dihydropyran-4-ones 4 and 5 in 66% and 76% yield respectively.
使用
碘苯二
醋酸酯和三甲基
溴化
硅或
碘化物处理顺式-2,3-二取代二氢
吡喃-4-酮 1,以81-93%的收率得到α-卤代二氢
吡喃-4-酮 2/3。然后在
钯(0)催化下,将α-
碘代二氢
吡喃-4-酮 3c进行交叉偶联,分别以66%和76%的收率得到α-芳基和α-
乙烯基二氢
吡喃-4-酮 4和5。