sulfuractivated and nonactivated species (13, 15) or irradiation of 1a under nonactivating conditions showed that the carboxylateanion in the position alpha to the electron-donating sulfur atom acts as a superior leaving group. This efficiency is drastically reduced for carboxylateanions in the alpha position. With the former substrates, the photochemical cyclization proceeds with high product yields. Quantum
A general and versatile synthesis of 3-phenylthio β-lactams as lead molecules for 3-methyl-2-azetidinones
作者:Seema Kanwar、S. D. Sharma
DOI:10.1002/jhet.5570440523
日期:2007.9
Ketene-imine cycloaddition using phosphorus oxychloride and benzenesulfonyl chloride under the described reaction conditions yielded trans 3-phenylthio 2-azetidinones in good yields. Desulfurization using Raney nickel and alkylation finally afforded trans 3-methyl-2-azetidinones in a stereoselective manner.
Studies towards C-3 functionalization of β-lactams using substituted allylsilanes
作者:RENU THAPAR、RESHMA、S S BARI
DOI:10.1007/s12039-016-1161-6
日期:2016.11
An effective and stereoselective synthesis of 3-(1′-methyl/phenylallyl)-3-phenylthio-β-lactams (3/4) using substituted allylsilane and Lewis acid is described. The reaction leads to the formation of a mixture of C-3substituted allyl β-Lactams. However, these compounds on desulphurisation using tri-n-butyltinhydride and Raney Ni provide two separable diastereomers of the reduced product. In the presence
A new synthetic approach for novel C-3 substituted β-lactams
作者:Sachin Madan、Renu Arora、P Venugopalan、S.S Bari
DOI:10.1016/s0040-4039(00)00865-0
日期:2000.7
An effective route to novel C-3 substituted β-lactams is described. This involves reaction of a β-lactam carbocation equivalent with active aromatic nucleophiles in the presence of a Lewis acid. The stereospecificity of the formation of mono-substituted products may be rationalised on the basis of the SnCl4 mediated intermediate complex A that reacts via an SN2 mechanism.
描述了制备新型C-3取代的β-内酰胺的有效途径。这涉及在路易斯酸存在下,β-内酰胺碳阳离子当量与活性芳族亲核试剂反应。可以基于经由S N 2机理反应的SnCl 4介导的中间配合物A来合理化单取代产物的形成的立体特异性。
Photodecarboxylative Additions of α-Thioalkyl-Substituted Carboxylates to Alkyl Phenylglyoxylates
Irradiations of alkyl phenylglyoxylates with sulfur-containing carboxylates yielded the corresponding photodecarboxylative addition products in moderate to good yields of 26-58%. Reductive photodimerization competed with decarboxylative addition in all cases. The reaction protocol was successfully transferred to a microreactor. With potassium 2-(methylsulfanyl)propionate, photoadditions gave diastereomeric