136551-45-6Relevant articles and documents
Enantioselective Hydroamination of Alkenes with Sulfonamides Enabled by Proton-Coupled Electron Transfer
Demaerel, Joachim,Graff, David E.,Knowles, Robert R.,Roos, Casey B.
supporting information, p. 5974 - 5979 (2020/04/27)
An enantioselective, radical-based method for the intramolecular hydroamination of alkenes with sulfonamides is reported. These reactions are proposed to proceed via N-centered radicals formed by proton-coupled electron transfer (PCET) activation of sulfonamide N-H bonds. Noncovalent interactions between the neutral sulfonamidyl radical and a chiral phosphoric acid generated in the PCET event are hypothesized to serve as the basis for asymmetric induction in a subsequent C-N bond forming step, achieving selectivities of up to 98:2 er. These results offer further support for the ability of noncovalent interactions to enforce stereoselectivity in reactions of transient and highly reactive open-shell intermediates.
Organo-Cation Catalyzed Asymmetric Homo/Heterodialkylation of Bisoxindoles: Construction of Vicinal All-Carbon Quaternary Stereocenters and Total Synthesis of (-)-Chimonanthidine
Chen, Si-Kai,Ma, Wen-Qiang,Yan, Zhi-Bo,Zhang, Fu-Min,Wang, Shao-Hua,Tu, Yong-Qiang,Zhang, Xiao-Ming,Tian, Jin-Miao
supporting information, p. 10099 - 10103 (2018/08/23)
A novel chiral spirocyclic amide (SPA)-derived triazolium organocatalyst has been designed and demonstrated to effect asymmetric homo- and heterodialkylations of various bisoxindoles, enabling enantioselective construction of vicinal all-carbon quaternary stereocenters. These reactions feature excellent enantio- and diastereoselectivities (up to 99% ee and >20:1 dr) as well as good to high yields (up to 89% over two steps). As an application of this methodology, the first asymmetric total synthesis of (-)-chimonanthidine has been achieved.
Modular Synthesis of Triazole-Based Chiral Iodoarenes for Enantioselective Spirocyclizations
Hempel, Christian,Maichle-M?ssmer, Caeciliea,Pericàs, Miquel A.,Nachtsheim, Boris J.
, p. 2931 - 2941 (2017/09/06)
A new triazole-based C1-symmetrical chiral iodoarene was synthesized in a highly modular route. Based on enzymatic kinetic resolution of an easily accessible propargylic alcohol both enantiomers were accessible in enantiopure form. By Huisgen-type azide-alkyne cycloaddtion a series of differently substituted iodoarenes was synthesized in high overall yields. Finally this novel iodoarene was successfully applied in the oxidative Kita cyclization of naphthol derivatives. Good yields and high ee values were obtained in the asymmetric spirocyclization via in situ generation of the hypervalent iodine species using mCPBA as the terminal oxidant. (Figure presented.).