An aryne precursor with a potential to perform domino aryne chemistry was proposed and synthesized. The reaction of this reagent with benzothioamide derivatives could afford 2,4-disubstituted benzothiazole with sequential incorporation of C-S, C-N, and C-C bonds on the consecutive three positions of the aryne precursor.
1,2-Benzdiyne equivalents possess the unique property that they can react with two arynophiles through iteratively generated 1,2- and 2,3-aryne intermediates. Upon rational modification on the second leaving group of these aryne precursors, a domino aryne annulation approach was developed through a nucleophilic-ene reaction sequence. Various benzo-fused N-heterocyclic frameworks were achievable under transition metal-free conditions with a broad substrate scope.
A convenient and efficient domino aryne process was developed under transition‐metal‐free conditions to generate a range of tetra‐ and pentacyclic ring systems. This transformation was realized via a 1,2‐benzdiyne through a nucleophilic and Diels–Alder reaction cascade using styrene as the diene moiety. Three new chemical bonds, namely one C−N and two C−C bonds, and two benzofused rings could be constructed concomitantly, which was made possible by distinct chemoselective control at both the 1,2‐aryne and 2,3‐aryne stages. Moreover, in‐depth studies were carried out on the domino aryne precursors and controlling the diastereoselectivity.
A chemoselective ring-opening protocol of the formal [2+2] cycloadducts of 3-triflyloxyarynes was developed to generate 2,3-aryne intermediate via Grob fragmentation. A variety of 1,3-di- and 1,2,3-trisubstituted arenes could be readily accessed through this [2+2] cycloaddition-2,3-aryne formation sequence. The regioselectivity in these transformations originates from the steric repulsion of the aliphatic chain.
Dynamic response is a key parameter for the engineering applications of MR damper. However, the response time has many different definitions, and which leads to a confusion of the measurement. Commonly, the response of MR damper in the new-designed status is focused, the instance after long-time use or standing-still has not been proposed. In this paper, the influence on the response time by the long-time standing-still is investigated, which shows that the response is largely lengthened. Next step, the measurement will be optimized, and the response of MR damper after long-time use will be in consideration.
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