Copper-Catalyzed β-Lactam Formation Initiated by 1,3-Azaprotio Transfer of Oximes and Methyl Propiolate
作者:Zhenjie Qi、Shaozhong Wang
DOI:10.1021/acs.orglett.1c01937
日期:2021.8.6
A copper(II)-catalyzed protocol to construct trans-configured β-lactams and spirocyclic β-lactams from oximes and methylpropiolate has been developed, which features excellent substrate flexibility and diastereoselectivity (up to >99:1 dr). In situ FT-IR mechanistic experiments support that ketene species might be involved in the formation of β-lactams.
已经开发了一种铜 (II) 催化的协议,用于从肟和丙炔酸甲酯构建反式配置的β-内酰胺和螺环 β-内酰胺,其具有出色的底物灵活性和非对映选择性(高达 >99:1 dr)。原位 FT-IR 机械实验支持乙烯酮物质可能参与 β-内酰胺的形成。
Palladium-Catalyzed Coupling Reactions of Thioimidate N-Oxides: Access to α-Alkenyl- and α-Aryl-Functionalized Cyclic Nitrones
作者:Julie Schleiss、Patrick Rollin、Arnaud Tatibouët
DOI:10.1002/anie.200905188
日期:2010.1.12
Surprisingly useful are thioimidate N‐oxides in the preparation of aryl‐ and vinyl‐substituted cyclic ketonitrones through the Liebeskind–Srogl reaction. This novel synthetic approach appears to be efficient and have a broad scope (see scheme).
An improved procedure for the preparation of β-thiohydroximates for glucosinolate synthesis
作者:Susan E. Cobb、Kate F. Morgan、Nigel P. Botting
DOI:10.1016/j.tetlet.2011.01.117
日期:2011.4
A novel and simple method is described for the synthesis of β-thiohydroximates from oximes and 2,3,4,6-tetra-O-acetyl-1-thio-β-d-glucopyranose, which are key intermediates in the synthesis of glucosinolates. The procedure involves the in situ formation of an oximyl chloride from the oxime, using inexpensive bleach, which is then reacted directly under basic conditions with the thioglucopyranose.
The regiochemistry of intramolecular n-alkenylnitrone additions: preparative and mechanistic implications
作者:Wolfgang Oppolzer、Samuel Siles、Roger L. Snowden、Bartholomeus H. Bakker、Martin Petrzilka
DOI:10.1016/s0040-4039(01)86596-5
日期:——
The opposite regiochemistry, observed for the reactions 7a → 8a and 7d → 8d, as compared with additions 7b → 9b, 7c → 9c and 7e → 9e, supports the hypothesis that in the transition state of nitrone-olefin additions the new C,C bond is more advanced than the C,0, bond. Further examples show the superimposition of substituent effects on this intramolecular control.
Alkyl aldoximes without a directing group undergo palladium-catalyzed C–H arylation with arylbromides to afford alkylaryl ketoximes in moderate to high yields. The reaction of electron-rich arylbromides and linear oximes proceeded to afford the coupling products in up to 98% yield. This reaction has broad scope and excellent functional group tolerance. Although reactions using hydroxyl oximes as