<scp>TEMPO‐Regulated</scp>Regio‐ and Stereoselective<scp>Cross‐Dihalogenation</scp>with Dual Electrophilic X<sup>+</sup>Reagents
作者:Yi Kong、Tongxiang Cao、Shifa Zhu
DOI:10.1002/cjoc.202100472
日期:2021.11
method could enable wide applications in organic synthesis, which was exemplified by divergent synthesis of two pharmaceuticals. Detailed mechanistic investigations via radical clock reaction, pinacol ring expansion and Hammett experiments were conducted, which confirmed the intermediacy of halonium ion. In addition, a dynamic catalytic model based on the versatile catalytic role of TEMPO was proposed
TEMPO 催化的交叉二卤化反应是通过氧化还原调节双亲电 X +试剂的复杂系统而建立的。形式上,ICl的,氯化溴,我2和Br 2产生在-原位,这使高区域选择性或立体选择性获得的iodochlorination,bromochlorination和均-二卤化产物无数与功能性的宽光谱。该方法条件温和,操作简单,可广泛应用于有机合成,例如两种药物的发散合成。通过详细的机械调查进行了自由基钟反应、频哪醇扩环和哈米特实验,证实了卤离子的中介作用。此外,提出了一种基于 TEMPO 多功能催化作用的动态催化模型来解释选择性结果。
Synthesis of Alkynyl-Glycinols by Lewis Acid Catalyzed Propargylic Substitution of Bis-Imidates
s derived from alkynyl-glycols. The cyclization proceeds selectively to give 4-alkynyl-oxazolines as the propargylic substitution products. Enantioenriched bis-imidates that contain an alkyl or trimethylsilyl substituent at the acetylene gave oxazolines with complete inversion of configuration. In turn, considerable racemization was observed in the cyclization of bis-imidates that contain a phenyl
A novel chalcogen-mediated metal-free oxyfunctionalization mode of ynamides for the synthesis of α-chalcogenyl acrylamides has been developed.
一种新颖的硒介导的无金属氧官能化模式已被开发用于合成α-硒基丙烯酰胺。
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
Fully Substituted Conjugate Benzofuran Core: Multiyne Cascade Coupling and Oxidation of Cyclopropenone
作者:Liangliang Yao、Qiong Hu、Li Bao、Wenjing Zhu、Yimin Hu
DOI:10.1021/acs.orglett.1c01304
日期:2021.7.2
multiyne cascade coupling has been developed. This chemistry provides a novel, simple, and efficient approach to synthesize fullysubstituted conjugate benzofuran derivatives from simple substrates under mild conditions. The density functional theory (DFT) calculations reveal that the unique homolytic cleavages of cyclopropenone and molecular oxygen are crucial to the success of this reaction.