Palladium-Catalyzed Electrochemical Allylic Alkylation between Alkyl and Allylic Halides in Aqueous Solution
作者:Yin-Long Lai、Jing-Mei Huang
DOI:10.1021/acs.orglett.7b00473
日期:2017.4.21
A new route for the direct cross-coupling of alkyl and allylic halides using electrochemical technique has been developed in aqueous media under air. Catalyzed by Pd(OAc)2, the Zn-mediated allylicalkylations proceed smoothly between a full range of alkyl halides (primary, secondary, and tertiary) and substituted allylic halides. Protection–deprotection of acidic hydrogen in the substrates is avoided
Thiourea–I2 as Lewis base–Lewis acid cooperative catalysts are developed for the iodochlorination of alkenes with in situ-generated iodinemonochloride (I–Cl). The Lewis base–Lewis acid cooperative system is sufficient to generate I–Cl from I2 with a chlorinating reagent at low temperature. Based on the solid-state structure of the active species, thiourea–I2 cooperatively captures I–Cl. By taking
硫脲-I 2作为路易斯碱-路易斯酸协同催化剂被开发用于用原位生成的一氯化碘(I-Cl)进行烯烃的碘氯化。刘易斯碱-路易斯酸协同体系足以在低温下用氯化剂从I 2生成I-Cl 。基于活性物质的固态结构,硫脲I 2协同捕获I Cl。通过利用I–Cl生成和在低温下控制I–Cl的优势,硫脲– I 2协同系统抑制了由高反应性游离I–Cl引起的副反应。
Regio- as well as stereoselective epoxide ring opening reactions using 3,3,3-trifluoroprop-1‑yne
Azido-difluoromethylthiolation of Alkenes with TMSN<sub>3</sub> and PhSO<sub>2</sub>SCF<sub>2</sub>H
作者:Yun-Tao Shen、Yu-Song Ran、Bo Jiang、Cui Zhang、Wei Jiang、Ya-Min Li
DOI:10.1021/acs.orglett.3c01562
日期:2023.6.23
An oxidative azido-difluoromethylthiolation of alkenes by employing TMSN3 as the azide source and PhSO2SCF2H as the difluoromethylthiolation reagent is reported. The present method is characterized by good functional group tolerance, broad substrate scope, and short reaction time, thereby providing an efficient access to syntheticallyuseful β-difluoromethylthiolated azides. Mechanistic studies indicate
报道了使用 TMSN 3作为叠氮化物源和 PhSO 2 SCF 2 H 作为二氟甲硫基化试剂对烯烃进行氧化叠氮基二氟甲硫基化。该方法具有良好的官能团耐受性、广泛的底物范围和短的反应时间,从而提供了合成有用的β-二氟甲硫基叠氮化物的有效途径。机理研究表明该反应涉及自由基途径。
Stereochemistry of Carbenic 1,2-Vinyl Shifts
作者:Wolfgang Kirmse、Siegfried Kopannia
DOI:10.1021/jo971691t
日期:1998.2.1
Various 1-phenylbut-3-enylidenes, (Ph)CCR2CH=CHR', were generated thermally and photolytically from tosylhydrazone (diazo) precursors. 1,2-Vinyl shifts, leading to 1,3-dienes, R'CH=CHC(Ph)=CR2, were found to predominate over gamma-C-H insertion (R = Me) and to compete with 1,2-H shifts (R = H). Intramolecular addition to the double bond was detected in the case of R = R' = Me. The resulting bicyclobutane is thermally stable and does not mediate the vinyl shift. Stereospecific migration of 1-propenyl groups (R' = Me), with retention of configuration, was observed on thermolysis and direct photolysis of appropriate substrates. These data exclude the intervention of a triplet diradical and point, to vinyl migration in the singlet manifold. Benzophenone-sensitized generation of the carbenes led to partial stereomutation but did not provide conclusive evidence for a triplet rearrangement (isomerization of the diene products could not be avoided under these conditions).