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Copper(II) acetate/acetic acid/O2 and potassium iodide/tert-butylhydroperoxide systems are shown to affect the selective oxidation of ring-fused aminals to dihydroquinazolines and quinazolinones, respectively. These methods enable the facile preparation of a number of quinazoline alkaloid natural products and their analogues.
Chua’s circuit, which is improved to integrate conveniently, is presented. A drive-response chaotic synchronization system is constructed, which possesses a certain stability, resisting-disturbance, and so on. By means of research, it can be concluded that the chaotic synchronization system is provided with the characteristic of chaos synchronization(More)
Pyrrolidine and related amines undergo asymmetric A(3) reactions in the presence of copper iodide and an easily accessible cocatalyst possessing both a carboxylic acid and a thiourea moiety. Propargylamines are obtained with up to 96% ee, and catalyst loadings can be as low as 1 mol %. Pyrrolidine-derived propargylamines, in the absence of directing groups,(More)
Reductive condensations of alcohols with aldehydes/ketones to generate ethers are catalyzed by a readily accessible thiourea organocatalyst that operates in combination with HCl. 1,1,3,3-tetramethyldisiloxane serves as a convenient reducing reagent. This strategy is applicable to challenging substrate combinations and exhibits functional group tolerance.(More)
Two catalysts, an amine HCl salt and a bisthiourea, work in concert to enable the generation of oxocarbenium ions under mild conditions. The amine catalyst generates an iminium ion of sufficient electrophilicity to enable 1,2-attack by an alcohol. Catalyst turnover is achieved by amine elimination with concomitant formation of an oxocarbenium intermediate.(More)
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