80639-68-5Relevant academic research and scientific papers
Asymmetric catalysis with a chiral-at-osmium complex
Wang, Guanghui,Zhou, Zijun,Shen, Xiang,Ivlev, Sergei,Meggers, Eric
, p. 7714 - 7717 (2020/07/27)
The first example of a chiral osmium catalyst is reported in which the overall chirality originates exclusively from a stereogenic metal center (metal-centered chirality) with all coordinating ligands being achiral. The non-C2-symmetric chiral-at-metal complex contains two cyclometalated 7-methyl-1,7-phenanthrolinium heterocycles which can be described as two chelating pyridylidene remote N-heterocyclic carbene (rNHC) ligands. The octahedral coordination sphere is completed with one CO and one acetonitrile ligand. A monodentate chiral oxazoline ligand is used as a chiral auxiliary ligand to obtain enantiomerically pure chiral-at-osmium complexes (>99?:?1 e.r.). Finally, it is demonstrated that the developed chiral-at-osmium complex is suitable for ring-closing enantioselective C(sp3)-H aminations, including the first example of catalytic enantioselective cyclizations of azidoformates to chiral 2-oxazolidinones.
Enantioselective Radical Construction of 5-Membered Cyclic Sulfonamides by Metalloradical C-H Amination
Hu, Yang,Lang, Kai,Li, Chaoqun,Gill, Joseph B.,Kim, Isaac,Lu, Hongjian,Fields, Kimberly B.,Marshall, McKenzie,Cheng, Qigan,Cui, Xin,Wojtas, Lukasz,Zhang, X. Peter
, p. 18160 - 18169 (2019/11/19)
Both arylsulfonyl and alkylsulfonyl azides can be effectively activated by the cobalt(II) complexes of D2-symmetric chiral amidoporphyrins for enantioselective radical 1,5-C-H amination to stereoselectively construct 5-membered cyclic sulfonami
Solution and Flash Vacuum Pyrolyses of 3-Arylpropanesulfonyl and 2-(Aryloxy)ethanesulfonyl Azides. Synthesis of 7-Membered Sultams
Abramovitch, Rudolph A.,Kress, Albert O.,McManus, Samuel P.,Smith, Maurice R.
, p. 3114 - 3121 (2007/10/02)
The solution and flash vacuum pyrolyses of 3-arylpropanesulfonyl azides have been studied and the results compared with those of the corresponding 2-arylethanesulfonyl azides.The best yields of 7-membered ring sultams are formed on solution decomposition in Freon 113.Hydrogen abstraction and solvent insertion products are obtained mainly in hydrocarbon solvents.The structure of the 7-membered sultams have been established unambiguously and an authentic sample of the parent 2,3,4,5-tetrahydro-1,2-thiazepine 1,1-dioxide prepared.Decomposition of 3-(2,6-dichlorophenyl)propanesulfonyl azide (22) leads to a 6,9-dichloro sultam (33c) via a 1,2-chlorine shift.FVP of 3-(2-mesityl)propanesulfonyl azide (20) gave a good yield of the 7-membered ring sultam (34)(1,2-methyl shift).FVP of 3-phenyl-1-propanesulfonyl azide (16) at 995 deg C (0.05 mm) gave, among other products, a 6.2percent yield of 5,6,7,8-tetrahydroquinoline (39).The formation of these products is discussed.Thermolysis of 2-(aryloxy)ethanesulfonyl azides gave the corresponding 7-membered ring sultams 27 as well.
