Visible Light-Induced Decarboxylative Acylarylation of Phenyl Propiolates with α-Oxocarboxylic Acids to Coumarins Catalyzed by Hypervalent Iodine Reagents under Transition Metal-Free Conditions
作者:Shuai Yang、Hui Tan、Wangqin Ji、Xiangbiao Zhang、Pinhua Li、Lei Wang
DOI:10.1002/adsc.201600721
日期:2017.2.2
No Abstract
没有摘要
Acyl Radicals from α-Keto Acids Using a Carbonyl Photocatalyst: Photoredox-Catalyzed Synthesis of Ketones
作者:Da-Liang Zhu、Qi Wu、David James Young、Hao Wang、Zhi-Gang Ren、Hong-Xi Li
DOI:10.1021/acs.orglett.0c02351
日期:2020.9.4
Acylradicals have been generated from α-keto acids using inexpensive and commercially available 2-chloro-thioxanthen-9-one as the photoredox catalyst under visible light illumination. These reactive species added to olefins or coupled with aryl halides via a bipyridyl-stabilized Ni(II) catalyst, enabling easy access to a diverse range of ketones. This reliable, atom-economical, and eco-friendly protocol
Sunlight-Driven Decarboxylative Alkynylation of α-Keto Acids with Bromoacetylenes by Hypervalent Iodine Reagent Catalysis: A Facile Approach to Ynones
作者:Hui Tan、Hongji Li、Wangqin Ji、Lei Wang
DOI:10.1002/anie.201503479
日期:2015.7.13
A novel and practical decarboxylativealkynylation of α‐keto acids with bromoacetylenes is catalyzed by hypervalent iodine(III) reagents when irradiation by sunlight at room temperature. The product ynones are generated in good yields. Experiments show that results obtained with blue light (λ=450–455 nm) are comparable to those obtained when using sunlight. Mechanistic studies demonstrate that the
Dual Hypervalent Iodine(III) Reagents and Photoredox Catalysis Enable Decarboxylative Ynonylation under Mild Conditions
作者:Hanchu Huang、Guojin Zhang、Yiyun Chen
DOI:10.1002/anie.201502369
日期:2015.6.26
combination of hypervalentiodine(III) reagents (HIR) and photoredoxcatalysis with visible light has enabled chemoselective decarboxylativeynonylation to construct ynones, ynamides, and ynoates. This ynonylation occurs effectively undermild reaction conditions at room temperature and on substrates with various sensitive and reactive functional groups. The reaction represents the first HIR/photoredox dual
α-ketoacids enabled by the Lewis acid activation. The in situ boron complex formation is confirmed by various spectroscopic measurements and mechanistic probing experiments, which facilitates various alkyl boronic acid addition to the carbonyl group and prevents the cleavage of the newly-formed C-C bond. Diversely substituted lactates can be synthesized from readily available alkyl boronic acids and ketoacids
由于所得烷氧基自由基容易断裂,分子间自由基加成到羰基上是困难的。迄今为止,酮的分子间自由基加成是构建季碳中心的一种有价值的方法,仍然是一项艰巨的合成挑战。在这里,我们报告了第一个可见光诱导的分子间烷基硼酸加成到 α-酮酸通过路易斯酸活化实现的。各种光谱测量和机械探测实验证实了原位硼配合物的形成,这有助于将各种烷基硼酸加成到羰基上,并防止新形成的 CC 键断裂。在室温下,仅在可见光照射下,无需任何额外试剂,即可由易得的烷基硼酸和酮酸合成不同取代的乳酸酯。这种硼活化方法可以扩展到作为自由基前体的烷基二氢吡啶与用于伯、仲和叔烷基自由基加成的外部硼试剂。在流动反应器中的无金属条件下,药学上有用的抗胆碱能前体很容易放大到数克。