由于甲硅烷基团容易迁移,甲硅烷基甲脒1与其碳烯形式1'处于平衡状态。1与各种取代的氟苯的反应随着亲核卡宾1'的插入而进行在混合试剂后进入最酸性的 C-H 键,不需要任何催化剂。根据 DFT 计算,通过三元过渡态结构进行的插入反应的经典解释需要高活化能。相反,预计将芳香底物中酸性最强的质子转移到卡宾碳上的活化势垒较低。下一步,形成的离子对向产物的无障碍重排完成了该过程。取代苯在与甲硅烷基甲脒反应中的反应性可以通过计算的C-H 氢的p K a (DMSO) 值粗略评估。具有 p K a的苯衍生物约 少于 31 个可以进行 C-H 插入。该反应提供缩醛胺作为第一批产物,它可以很容易地通过酸水解转化为相应的醛。由于甲硅烷基甲脒1对许多官能团具有耐受性,该反应可应用于多种苯衍生物,使其成为有机合成应用的可靠策略。
3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors. 3. 7-(3,5-Disubstituted-[1,1'-biphenyl]-2-yl)-3,5-dihydroxy-6-heptenoic acids and their lactone derivatives
摘要:
The syntheses of a series of 7-(3,5-disubstituted [1,1'-bephenyl]-2-yl)-3,5-dihydroxy-6-heptenoic acids and their lactones are reported. Intrinsic 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitory activity is enhanced markedly when the biphenyl moiety is substituted by chloro or methyl groups at positions 3 and 5 and a fluoro group at position 4'. These substitutions, followed by resolution, provided compounds 100(+) and 110(+) with 2.8 times the intrinsic inhibitory activity of compactin. Compound 100(+) was shown to possess the same chirality in the lactone ring as compactin by single-crystal X-ray crystallography.
3-Hydroxy-3-methylglutaryl-coenzyme A reductase inhibitors. 3. 7-(3,5-Disubstituted-[1,1'-biphenyl]-2-yl)-3,5-dihydroxy-6-heptenoic acids and their lactone derivatives
作者:G. E. Stokker、A. W. Alberts、P. S. Anderson、E. J. Cragoe、A. A. Deana、J. L. Gilfillan、J. Hirshfield、W. J. Holtz、W. F. Hoffman
DOI:10.1021/jm00152a002
日期:1986.2
The syntheses of a series of 7-(3,5-disubstituted [1,1'-bephenyl]-2-yl)-3,5-dihydroxy-6-heptenoic acids and their lactones are reported. Intrinsic 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitory activity is enhanced markedly when the biphenyl moiety is substituted by chloro or methyl groups at positions 3 and 5 and a fluoro group at position 4'. These substitutions, followed by resolution, provided compounds 100(+) and 110(+) with 2.8 times the intrinsic inhibitory activity of compactin. Compound 100(+) was shown to possess the same chirality in the lactone ring as compactin by single-crystal X-ray crystallography.
Latent Carbene in Diaminomethylation of Benzenes: Mechanism and Practical Application
作者:Georgyi Koidan、Anastasiia N. Hurieva、Alexander B. Rozhenko、Uwe Manthe、Tobias Spengler、Serhii Zahorulko、Tetiana Shvydenko、Aleksandr Kostyuk
DOI:10.1021/acs.joc.3c00470
日期:2023.6.2
predicted for a transfer of the most acidic proton in the aromatic substrate to the carbene carbon. As the next step, a barrierless rearrangement of the formed ionpair toward the product completes the process. The reactivity of substituted benzenes in the reaction with silylformamidine can be roughly assessed by calculated pKa (DMSO) values for the C–H hydrogens. Benzene derivatives having pKa approx
由于甲硅烷基团容易迁移,甲硅烷基甲脒1与其碳烯形式1'处于平衡状态。1与各种取代的氟苯的反应随着亲核卡宾1'的插入而进行在混合试剂后进入最酸性的 C-H 键,不需要任何催化剂。根据 DFT 计算,通过三元过渡态结构进行的插入反应的经典解释需要高活化能。相反,预计将芳香底物中酸性最强的质子转移到卡宾碳上的活化势垒较低。下一步,形成的离子对向产物的无障碍重排完成了该过程。取代苯在与甲硅烷基甲脒反应中的反应性可以通过计算的C-H 氢的p K a (DMSO) 值粗略评估。具有 p K a的苯衍生物约 少于 31 个可以进行 C-H 插入。该反应提供缩醛胺作为第一批产物,它可以很容易地通过酸水解转化为相应的醛。由于甲硅烷基甲脒1对许多官能团具有耐受性,该反应可应用于多种苯衍生物,使其成为有机合成应用的可靠策略。