An efficient approach to the synthesis of 4H-1-benzothiopyran-4-ones via intramolecular Wittig reaction
作者:Pradeep Kumar、Ashok T. Rao、Bipin Pandey
DOI:10.1039/c39920001580
日期:——
The reaction of S-acyl(aroyl)thiosalicylic acids 2 with N-phenyl(triphenylphosphoranylidene)ethenimine 3 in stepwise fashion leads to the acylphosphoranes 5 which subsequently undergo intramolecular Wittig cyclization on the thiolester carbonyl to afford the 4H-1-benzothiopyran-4-ones 7 in excellent yields.
A highly enantioselective access to chiral chromanones and thiochromanones via copper-catalyzed asymmetric conjugated reduction of chromones and thiochromones
作者:Donglu Xiong、Wenxi Zhou、Zhiwu Lu、Suping Zeng、Jun (Joelle) Wang
DOI:10.1039/c7cc03939e
日期:——
chemistry and drug discovery. A highly efficient copper-catalyzed asymmetric conjugated reduction of chromones is developed to give chiral chromanones with good yields (80–99%) and excellent ee values (94–>99% ee). Particularly noteworthy is that chiral thiochromanones are also constructed using this method in 74–87% yields with 96–97% ee. The established asymmetric synthesis paves the way for their
Chemoselective Reduction of Vinylogous Thioesters of Thiochromones
作者:Pradeep Kumar、Ashok T. Rao、Bipin Pandey
DOI:10.1080/00397919408010253
日期:1994.12
The chemoselective reduction of vinylogous thioesters of thiochromones 3 into thiochromanones 4 is described.
A new synthesis of 4H-1-benzothiopyran-4-ones using (trimethylsilyl)methylenetriphenylphosphorane
作者:Pradeep Kumar、Mandar S Bodas
DOI:10.1016/s0040-4020(01)00977-2
日期:2001.11
The reaction of silyl ester of S-acyl(aroyl) thiosalicylic acids 3 with (trimethylsilyl)methylenetriphenylphosphorane 4 in step wise fashion leads to the acylphosphoranes 7, which subsequently undergo intramolecular Wittig cyclization on the thiolester carbonyl to afford the 4H-1-benzothiopyran-4-ones 8 in good to excellent yields.
S-酰基(芳酰基)硫代水杨酸3的甲硅烷基酯与(三甲基甲硅烷基)亚甲基三苯基膦烷4的逐步反应导致酰基膦酸酯7,其随后在硫酯羰基上进行分子内Wittig环化,得到4 H -1-苯并噻喃-4-ones 8的产量好至极好。