- Rhodium-Catalyzed Spiro Indenyl Benzoxazine Synthesis via C-H Activation/Annulation of 3-Aryl-2H-Benzo[b][1,4]oxazines and Alkynes
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The rhodium (III)-catalyzed annulation of 3-Aryl-2H-Benzo[b][1,4]oxazines with alkynes via C–H activation has been developed. This reaction afforded a series of spiro indenyl benzoxazine in high yields under mild reaction condition with good functional group tolerance.
- Tan, Heng,Laishram, Ronibala Devi,Zhang, Xuexin,Shi, Guangrui,Li, Kangkui,Chen, Jingchao
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supporting information
p. 4542 - 4546
(2020/07/04)
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- A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines
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A metal-free hydrogenation of 3-substituted 2H-1,4-benzoxazines has been successfully realized with 2.5 mol% of B(C6F5)3 as a catalyst to furnish a variety of 3,4-dihydro-2H-1,4-benzoxazines in 93-99% yields. Up to 42% ee was also achieved for the asymmetric hydrogenation with the use of a chiral diene and HB(C6F5)2.
- Wei, Simin,Feng, Xiangqing,Du, Haifeng
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p. 8026 - 8029
(2016/09/09)
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- Method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives
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The invention provides a method for preparing 3,4-dihydrobenzo[b][1,4]oxazine derivatives. The method comprises the following step: carrying out reduction reaction on [b][1,4]oxazines in the presence of hydrogen gas by using B(C6F5)3 as a catalyst to obtain the mixture containing the 3,4-dihydrobenzo[b][1,4]oxazines disclosed as Formula I. Benzo[b][1,4]oxazines in different structures are used as a substrate to synthesize the benzo[b][1,4]oxazines at high yield by using the B(C6F5)3 as the catalyst. The method has the advantages of cheap and accessible raw materials, high reaction activity, no participation of transition metals and wide substrate application range, and has huge industrialization potential.
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- Highly enantioselective spinol-derived phosphoric acid catalyzed transfer hydrogenation of diverse C=N-containing heterocycles
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A highly efficient and enantioselective hydrogenation of diversely substituted C=N-containing heterocyclic compounds such as 3-aryl-1,4-benzoxazines and 2-arylquinolines was experimentally explored by using 1,1′-spirobiindane-7,7′-diol-derived chiral phosphoric acids as the catalyst. This method provides straightforward access to the corresponding tetrahydroquinolines and dihydro-2H-1,4-benzothiazines in high yields (85-99%) with excellent enantioselectivities (91-99%). The attractive features of this procedure, which include mild reaction conditions, operational simplicity, relatively low catalyst loading (1 mol-%), and high levels of enantioselectivities, make it a useful approach for the practical synthesis of optically active nitrogen-containing aromatic heterocycles.
- Zhang, Yiliang,Zhao, Rong,Bao, Robert Li-Yuan,Shi, Lei
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supporting information
p. 3344 - 3351
(2015/05/20)
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- 4,5-Dihydropyrrolo[1,2-a]quinoxalines: A tunable and regenerable biomimetic hydrogen source
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A series of tunable and regenerable biomimetic hydrogen sources, 4,5-dihydropyrrolo[1,2-a]quinoxalines, have been synthesized and applied in biomimetic asymmetric hydrogenation of 3-aryl-2H-benzo[b][1,4]oxazines and 1-alkyl-3-aryl-quinoxalin-2(1H)-ones, providing the chiral amines with up to 92% and 89% ee, respectively.
- Chen, Zhang-Pei,Chen, Mu-Wang,Guo, Ran-Ning,Zhou, Yong-Gui
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supporting information
p. 1406 - 1409
(2014/04/03)
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- First I2-K2CO3-promoted sequential C-N and C-O bond forming approach for one-pot synthesis of 1,4-benzoxazines
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I2-K2CO3 combination has been found to be an efficient, reusable, and inexpensive catalyst system for the one-pot synthesis of 3-aryl-2H-benz[1,4]oxazine via rapid CN and C-O bond formation. No by-product formation, operat
- Singh, Sunil K.,Bajpai, Anil K.,Saini, Rajesh
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p. 7132 - 7135
(2013/12/04)
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- Iridium-catalyzed asymmetric hydrogenation of 3-substituted 2H-1,4-benzoxazines
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The highly enantioselective hydrogenation of 3-aryl-2H-1,4-benzoxazines was achieved using the (cyclooctadiene)iridium chloride dimer/(S)-SegPhos/iodine {[Ir(COD)Cl]2/(S)-SegPhos/I2} system as catalyst with up to 92% ee. The 3-styryl
- Gao, Kai,Yu, Chang-Bin,Wang, Duo-Sheng,Zhou, Yong-Gui
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experimental part
p. 483 - 488
(2012/05/04)
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