An Extremely Facile Synthesis of Furans, Pyrroles, and Thiophenes by the Dehydrative Cyclization of Propargyl Alcohols
摘要:
Furans, pyrroles, and thiophenes are efficiently prepared by gold-catalyzed dehydrative cyclizations of readily available, heteroatom-substituted propargylic alcohols. The reactions are rapid, high-yielding, and procedurally simple, giving essentially pure aromatic heterocycles in minutes under open-flask conditions with catalyst loadings as low as 0.05 mol %.
Nucleophilic Organic Base DABCO-Mediated Chemospecific Meinwald Rearrangement of Terminal Epoxides into Methyl Ketones
作者:Siqi Li、Yi Shi、Pingfan Li、Jiaxi Xu
DOI:10.1021/acs.joc.8b03171
日期:2019.4.5
various epoxides was investigated. 2-Aryl-, alkenyl-, and alkynylepoxides generate the corresponding methyl ketones chemospecifically in good to excellent yields. The current DABCO-mediated Meinwald rearrangement of epoxides features readily accessible starting materials, a wide substrate scope, a transition-metal- and acid-free environment, and chemospecificity in the isomerization of epoxides.
Chemo-, regio-, and stereo-selective perfluoroalkylations by a Grignard complex with zirconocene
作者:Motohiro Fujiu、Kazuyuki Negishi、Jie Guang、Paul G. Williard、Shigeki Kuroki、Koichi Mikami
DOI:10.1039/c5dt03039k
日期:——
The synthesis of highly reactive perfluoroalkyl Grignard reagents with early transition metal zirconocene complexes and their new types of highly chemo-, regio-, and stereo-selective perfluoroalkylation reactions are reported with epoxides in particular. The zirconocene complex is advantageous in activating the perfluoroalkyl Grignard species. The zirconocene·Grignard complexes were clarified by DOSY
Leveraging the Micellar Effect: Gold-Catalyzed Dehydrative Cyclizations in Water at Room Temperature
作者:Stefan R. K. Minkler、Nicholas A. Isley、Daniel J. Lippincott、Norbert Krause、Bruce H. Lipshutz
DOI:10.1021/ol403402h
日期:2014.2.7
The first examples of gold-catalyzed cyclizations of diols and triols to the corresponding hetero- or spirocycles in an aqueous medium are presented. These reactions take place within nanomicelles, where the hydrophobic effect is operating, thereby driving the dehydrations, notwithstanding the surrounding water. By the addition of simple salts such as sodium chloride, reaction times and catalyst loadings
Efficient silylation reactions of propargyl epoxides catalyzed by copper catalyst have been developed. Under mild reaction conditions, the tri- and tetrasubstituted functionalized allenols and alkenes could be selectively obtained in moderate to high yields via tuning the bases and solvents used in the reactions. This work provides straightforward and efficient approaches to the synthesis of multifunctionalized
Generation, optimization and characterization of novel anti-prion compounds
作者:Andrea Altieri、Evgeny A. Spiridonov、Semen I. Sivtzev、Daisuke Ishibashi、Silvia Biggi、Noriyuki Nishida、Emiliano Biasini、Alexander V. Kurkin
DOI:10.1016/j.bmc.2020.115717
日期:2020.11
the chemical space exploration around the anti-prion compound BB 0300674 in order to gain an understanding of its Structure Activity Relationships (SARs). A series of 43 novel analogues, based on four different chemical clusters, were synthetized and tested against PrPSc and mutant PrP toxicity assays. From this biological screening, two compounds (59 and 65) emerged with a 10-fold improvement in anti-prion