Browsing by Author "Tu, Shu Jiang"
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Item Catalytic arylsulfonyl radical-triggered 1,5-enyne-bicyclizations and hydrosulfonylation of α,β-conjugates(2015) Chen, Zhen Zhen; Liu, Shuai; Hao, Wen Juan; Xu, Ge; Wu, Shuo; Miao, Jiao Na; Jiang, Bo; Wang, Shu Liang; Tu, Shu Jiang; Li, Guigen (TTU)A catalytic bicyclization reaction of 1,5-enynes anchored by α,β-conjugates with arylsulfonyl radicals generated in situ from sulfonyl hydrazides has been established using TBAI (20 mol%) and Cu(OAc)2 (5 mol%) as co-catalysts under convenient conditions. In addition, the use of benzoyl peroxide (BPO) as the oxidant and pivalic acid (PivOH) as an additive was proven to be necessary for this reaction. The reactions occurred through 5-exo-dig/6-endo-trig bicyclizations and homolytic aromatic substitution (HAS) cascade mechanisms to give benzo[b]fluorens regioselectively. A similar catalytic process was developed for the synthesis of γ-ketosulfones. These reactions feature readily accessible starting materials and simple one-pot operation.Item Copper-Catalyzed Annulation–Cyanotrifluoromethylation of 1,6-Enynes Toward 1-Indanones via a Radical Process(2020) Zhang, Tian Shu; Hao, Wen Juan; Cai, Pei Jun; Li, Guigen (TTU); Tu, Shu Jiang; Jiang, BoA new Cu(II)-catalyzed annulation–cyanotrifluoromethylation of 1,6-enynes with Togni's reagent and trimethylsilyl cyanide (TMSCN) has been established, enabling the direct construction of trifluoromethylated 1-indanones with an all-carbon quaternary center in good yields. This reaction was performed by using low-cost Cu(OTf)2 as the catalyst and Togni's reagent as both the radical initiator and a CF3 source, providing an efficient protocol for building up an 1-indanone framework with wide functional group compatibility. The reaction mechanism was proposed through a radical triggered addition/5-exo-dig cyclization/oxidation/nucleophilic cascade.Item Double SO2 Insertion into 1,7-Diynes Leading to Functionalized Naphtho[1,2-c]thiophene 2,2-dioxides(2018) Wang, Ai Fang; Hao, Wen Juan; Zhu, Yi Long; Li, Guigen (TTU); Zhou, Peng; Tu, Shu Jiang; Jiang, BoA novel metal-free double SO2 insertion/multicomponent bicyclization cascade of benzene-linked 1,7-diynes has been established by treatment with aryldiazonium tetrafluoroborates and DABCO-bis(sulfur dioxide) under redox-neutral conditions, providing a range of dual sulfone-containing naphtho[1,2-c]thiophene 2,2-dioxides with generally high stereoselectivity. The reaction pathway is proposed to proceed through the sequence of arylsulfonyl-radical-induced 6-exo-dig/5-endo-trig bicyclization, H-abstraction, and diazotization.Item Fe(III)-catalyzed bicyclization of yne-allenones with indoles for the atom-economic synthesis of 3-indolyl cyclobutarenes(2018) Li, Heng; Hao, Wen Juan; Li, Guigen (TTU); Tu, Shu Jiang; Jiang, BoA new Fe(III)-catalyzed bicyclization reaction of yne-allenones with indoles has been established, enabling the direct construction of cyclobuta[a]naphthalen-4-ols with an all-carbon quaternary center in good to excellent yields. This reaction was performed by using low-cost FeCl3 as the catalyst and EtOH as the environmentally benign solvent, providing a green protocol for constructing the cyclobutarene framework with a high degree of atom economy and functional group compatibility. The reaction mechanism was proposed to proceed through a [2 + 2] cycloaddition/1,6-conjugate addition cascade.