Preparation of asymmetric phase-transfer catalyst, 1,4-bis((4s,5s)-1,3-bis(3,5-di-tert-butylbenzyl)-4,5-diphenylimidazolidin-2-ylidene)piperazine-1,4-diium chloride
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Ang, Esther Cai Xia,Tan, Choon-Hong,Ye, Xinyi
p. 274 - 293
(2020/10/12)
Enantioselective Oxidation of Alkenes with Potassium Permanganate Catalyzed by Chiral Dicationic Bisguanidinium
Chiral anion-controlled ion-pairing catalysis was demonstrated to be a wide-ranging strategy that can utilize a variety of cationic metal species. In a similar manner, we envision a complementary strategy using chiral cation in partnership with inorganic anionic metal salts. Herein, we report a chiral dicationic bisguanidinium-catalyzed asymmetric oxidation reaction of alkenes with potassium permanganate. Chiral induction is attributed to ion-pairing interaction between chiral cation and enolate anion. The success of the current permanganate oxidation reaction together with mechanistic insights should provide inspiration for expansion to other anionic metal salts and would open up new paradigms for asymmetric transition metal catalysis, phase-transfer catalysis, and ion-pairing catalysis.
Wang, Chao,Zong, Lili,Tan, Choon-Hong
supporting information
p. 10677 - 10682
(2015/09/28)
A dynamic kinetic asymmetric transformation in the α-hydroxylation of racemic malonates and its application to biologically active molecules
(Chemical Equation Presented) Sly like a "DBFOX": The chiral α-hydroxy malonate 2 can be prepared in high yield and with up to 98% ee from racemic malonate 1 through α-hydroxylation using oxaziridine 3 and is catalyzed by the (R,R)-DBFOX-Ph/NiII/sup