Diastereoselective Synthesis of Benzoxanthenones
Diastereoselective Synthesis of Benzoxanthenones
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苯并杂蒽酮的非对映选择性合成
DOI：
10.1002/asia.201901727
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发表时间：
2020
期刊：
影响因子：
--
通讯作者：
Kozlowski, Marisa C.
中科院分区：
文献类型：
--
作者：
Neuhaus, William C.;Kozlowski, Marisa C.
开发了一种氧化催化钒（V）体系，通过串联氧化、氧化偶联和4+2环化反应，一锅法从相应的烯基苯酚单体中得到天然不丰富的碳环酮非对映异构体。该体系被应用于其他两个类似物的carpanone的合成。温和的氧化性银盐被用作末端氧化剂以使产生天然非对映异构体的carpanone的背景氧化最小化。此外，第一个例子的对映选择性氧化苯并咕吨酮的形成报告。溶剂极性对对映体选择性有很强的影响，与涉及钒席夫碱催化剂在环化步骤期间与烯基酚的醇部分结合的机制一致。
An oxidative catalytic vanadium(V) system was developed to access the naturally nonabundant diastereomers of carpanone from the corresponding alkenyl phenol monomer in one pot by tandem oxidation, oxidative coupling, and 4+2 cyclization. This system was applied to the synthesis of two other analogues of carpanone. Mild oxidizing silver salts were used as the terminal oxidant to minimize background oxidation which produces the natural diastereomer of carpanone. Further, the first examples of enantioselective oxidative benzoxanthenone formation are reported. Solvent polarity has a strong effect on enantioselectivity, consistent with a mechanism involving binding of vanadium Schiff base catalysts to the alcoholic moiety of the alkenyl phenols during the cyclization step.