Synthesis of <i>N</i>-alkylated 2-pyridones through Pummerer type reactions of activated sulfoxides and 2-fluoropyridine derivatives
作者:Gang Hu、Jiaxi Xu、Pingfan Li
DOI:10.1039/c8ob00860d
日期:——
excellent yields through a one-pot procedure involving either normal or interrupted Pummerer reactions between triflic anhydride activated sulfoxides and 2-fluoropyridine derivatives, followed by hydrolysis. This is a rare case that uses 2-fluoropyridine as a nucleophile in Pummerer type reactions.
Herein we reported an efficient palladium-catalyzed enantioselective arylation of both alkyl and aryl sulfenate anions to deliver various chiral sulfoxides in good yields (up to 98%) with excellent enantioselectivities (up to 99% ee) by the use of our developed chiral O,P-ligands (PC-Phos). PC-Phos are easily prepared in shortsteps from inexpensive commercially available starting materials. The single-crystal
Synthesis of <i>N</i>-Alkylpyridin-4-ones and Thiazolo[3,2-<i>a</i>]pyridin-5-ones through Pummerer-Type Reactions
作者:Jingjia Huang、Gang Hu、Shaoyu An、Dongding Chen、Minglei Li、Pingfan Li
DOI:10.1021/acs.joc.9b01672
日期:2019.8.2
involving either normal or interrupted Pummerer reactions between triflic anhydride-activated sulfoxides and 4-fluoropyridine derivatives, followed by hydrolysis. On the other hand, triflic anhydride-activated benzyl 6-fluoro-2-pyridyl sulfoxide could react with alkenes or alkynes to afford thiazolo[3,2-a]pyridin-5-ones, via the pyridinium salt intermediates.
N-烷基化的4-吡啶酮是通过一锅法获得的,该方法涉及三氟甲酸酐活化的亚砜和4-氟吡啶衍生物之间的正常或间断的Pummerer反应,然后进行水解。另一方面,三氟甲磺酸酐活化的苄基6-氟-2-吡啶基亚砜可以通过吡啶鎓盐中间体与烯烃或炔烃反应生成噻唑并[3,2 - a ]吡啶-5-酮。
Tetrabutylammonium tribromide impregnated MCM-48 as a heterogeneous catalyst for selective oxidation of sulfides
作者:Prasanta Gogoi、Sukanya Hazarika、Pranjit Barman
DOI:10.1039/c5ra04573h
日期:——
We report here tetrabutylammoniumtribromide supported on MCM-48 as a highly efficient heterogeneous catalyst for the selective oxidation of sulfides, in ethanolic medium using hydrogen peroxide as an oxidant. The aforementioned oxidation reactions were found to proceed rapidly (20 min) and in good yield (85–99%) (17 examples). The oxidation products were characterized by 1H NMR, 13C NMR and elemental
我们在此报告了在MCM-48上负载的三丁基四溴化铵作为一种高效多相催化剂,用于在使用过氧化氢作为氧化剂的乙醇介质中选择性氧化硫化物。发现上述氧化反应进行迅速(20分钟),收率良好(85-99%)(17个实例)。氧化产物通过1 H NMR,13 C NMR和元素分析进行表征。通过TEM,XRD和BET表面积测量来分析催化性能。没有观察到底物的过氧化(通过GC分析),并且该催化剂有效地再循环了五个连续的循环,而其催化活性没有任何显着的损失。
Competitive and Selective Csp3Br versus Csp2Br Bond Activation in Palladium-Catalysed Suzuki Cross-Coupling: An Experimental and Theoretical Study of the Role of Phosphine Ligands
hindered phosphineligands such as P(o‐tol)3 and P(1‐naphthyl)3 reversed the selectivity, conducting the cross‐coupling at the Csp2‐Br. Identical trends were observed in external competition experiments carried out with bromomethyl sulfoxide and different substituted bromoarenes. DFT and DFT/MM calculations showed that the selectivity observed is mainly due to the different facility of the ligands to dissociate