Alternative Palladium-Catalyzed Vinylic C−H Difluoroalkylation of Ketene Dithioacetals Using Bromodifluoroacetate Derivatives
作者:Shuangquan Tian、Xiaoning Song、Dongsheng Zhu、Mang Wang
DOI:10.1002/adsc.201701554
日期:2018.4.3
A palladium‐catalyzedcross‐coupling of α‐oxo ketene dithioacetals and bromodifluoroacetate derivatives has been developed for the synthesis of a class of CF2‐containing tetra‐substituted olefins, which has potential to extend to drug design and material application. The process is proposed to involve two single electron transfer processes accompanied by an alternative loop from palladium(0) to palladium(I)
Unmasking Dipole Character of Acyl Ketene Dithioacetals via a Cascade Reaction with Arynes: Synthesis of Benzo[<i>b</i>]thiophenes
作者:Parul Garg、Anand Singh
DOI:10.1021/acs.orglett.8b00053
日期:2018.3.2
An unusual strategy toward novel substituted benzo[b]thiophenes has been developed. The generation of arynes in the presence of acyl ketene dithioacetals resulted in a cascade reaction involving [3 + 2] cycloaddition, and a dealkylative arylation of a thioether moiety to afford 2,3-disubstuted benzo[b]thiophenes. This route represents an expeditious approach to benzothiophenes that employs acyl ketene
已经开发出一种针对新型取代的苯并[ b ]噻吩的不寻常策略。在酰基乙烯酮二硫缩醛的存在下生成芳烃导致级联反应,涉及[3 + 2]环加成反应,以及硫醚部分的脱烷基芳基化反应,得到2,3-二取代的苯并[ b ]噻吩。该途径代表了采用酰基乙烯酮二硫缩醛作为偶极子的苯并噻吩的一种快速方法。
Photoinduced C(sp<sup>2</sup>)–H/C(sp<sup>2</sup>)–H Cross-Coupling of Alkenes: Direct Synthesis of 1,3-Dienes
作者:Qi Xu、Baihui Zheng、Xiaoxuan Zhou、Ling Pan、Qun Liu、Yifei Li
DOI:10.1021/acs.orglett.9b04201
日期:2020.3.6
A highly concise route to substituted 1,3-dienes from vinylarenes and ketene dithioacetals under photoinduced cross-coupling reaction is described. The reaction proceeded in a highly regio- and stereoselective manner and showed broad functional group tolerance. More than 35 substituted 1,3-dienes were synthesized with good to excellent yields through the construction of the Csp2-Csp2 bond without using
作者:Chen Jin、Cailin Ning、Yating Sui、Bingxin Zhang、Xinxin Li、Ling Pan、Qun Liu、Yifei Li
DOI:10.1021/acs.orglett.4c00682
日期:2024.3.22
Direct alkene C–H/N–H cross dehydrogenative coupling is an infrequent, highly challenging transformation. Herein, a photoredox radical–radical cross-coupling reaction between ketene dithioacetal as a persistent alkene radical cation and azole nitrogen center radical (NCR) was developed. This direct alkene amination proceeded through a synergistic photoredox and cobalt catalysis, with only H2 evolution
Infrared spectra and theoretical study of the conformations of substituted benzoylketene-S,S-acetals
作者:A. Perjéssy、W. -D. Rudorf、D. Loos、Z. Šusteková
DOI:10.1007/bf00811088
日期:1994.12
The C=O stretching frequencies of substituted benzoylketene-S,S-dimethylacetals (1a-1o) and benzoylketene-S,S-ethyleneacetals (2a-2m) were measured in CHCl3 and CCl4 and correlated with the Hammett substituent constants. The correlations were split into two different and well separated lines for compounds containing electron donor and electron acceptor substituents, which were assigned to s-trans and s-cis quasiplanar conformations. The correlations of carbonyl stretching frequencies with C=O bond orders and oxygen atom charge densities calculated using the semiempirical AM1 method reveal similar results consistent with assignments of structures 1 and 2 to two quasiplanar conformations. The preparation of some new benzoylketene-S,S-acetals is reported as well.