Publications by authors named "Chenglong Du"

This paper considers the problem of fuzzy overhead crane system modelling and finite-time stability/boundedness via sliding mode control (SMC) method. Due to the strong coupling of control input, the fuzzy technique is utilized to linearize the overhead crane system and a fuzzy overhead crane model is established with appropriate membership functions. Considering the bad effect, including the swing of hook and plates, the external disturbances of the friction and air resistances, is inevitable during the transportation of copper electrode plates, the SMC method is adopted to stabilize the fuzzy system and robust to these interference signals.

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The first asymmetric total synthesis of aspidosperma alkaloid (+)-winchinine B was achieved in 12 steps from commercially available materials. A new synthetic strategy which features an efficient aza-Michael addition, a ruthenium-catalyzed transfer dehydrogenation, and an intramolecular palladium-catalyzed oxidative coupling was adopted to install the ABC tricycle system. A one-pot process involving carbonyl reduction/iminium formation/intramolecular conjugate addition developed by our group was utilized to construct the D ring moiety.

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A double cyclization strategy was developed to construct the common tetracyclic core of calyciphylline B-type alkaloids. Key features of the synthesis included asymmetric Evans alkylation, ring-closing metathesis reaction, intermolecular amidation, intramolecular aza-Michael addition, and aldol condensation reactions. This strategy may be applied to the total syntheses of this type of natural product.

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The first total synthesis of paucidirinine (1d), a highly congested aspidofractinine alkaloid containing a special contracted five-membered lactam ring, was achieved in 10 steps with 8% overall yield from commercially available materials. Several key maneuvers, including tandem enamination/[4 + 2] cycloaddition reaction and SmI-promoted radical cyclization, were featured in this potentially scalable strategy.

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A visible-light promoted single electron oxidation of ether enabled by photoredox catalysis has been accomplished. This procedure initiates a novel radical insertion/cyclization cascade reaction to generate phenanthridines and isoquinolines from easily available isocyanides under mild reaction conditions.

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Based on the well-defined five-membered aryl gold(iii) complexes, [Au(tpy)X] ( and ) and [AuBr(Ph)(tpy)] (), as well as the aryl gold(iii) complex [AuCl(Ph)(tpy)] () (tpy = 2-(-tolyl)pyridine) as reliable models, we present a detailed study of the mechanism for gold(iii)-catalyzed oxidative cross-coupling reactions between cycloaurable arenes and arylboronic acids. Here we report the direct evidence for a mechanistic proposal including arene C-H activation, transmetallation and biaryl reductive elimination. The chelation-assisted C-H activation strategy has been used for the development of the gold(iii)-catalyzed C-H bond arylation of arenes with aryl reagents to forge extended π-conjugated systems.

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Double role: A traceless directing group also acts as an internal oxidant in a novel Rh(III) -catalyzed protocol developed for the synthesis of ortho-alkenylated tertiary anilines. A five-membered cyclometalated Rh(III) complex is proposed as a plausible intermediate and confirmed by X-ray crystallographic analysis.

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