Cooperative Cation Binding Catalysis For Direct Generation Of Two Contiguous Tertiary And Quaternary Stereogenic Centers

Good Essays

Abstract In this study, the concept of cooperative cation binding catalysis was elegantly applied for direct generation of two contiguous tertiary and quaternary stereogenic centers. Using a highly accessible chiral oligoethylene glycol (oligoEG) as a cation-binding catalyst, asymmetric Mannich reaction of α-thiocyanato cyclic ketones as Mannich donors was performed with α-amido sulfones as the bench-stable imine precursors in the presence of potassium fluoride as the base, affording α-thiocyanato-β-amines possessing tetra-substituted C-SCN centers. The salient features of this process include (a) a transition-metal free and operationally simple procedure, (b) direct use of α- amido sulfones as bench-stable precursors of sensitive imines, …show more content…

In particular, chiral compounds with β-amino-α-thiocyanate moieties are rarely explored in the medicinal chemistry area because of their synthetic difficulty,[5] although they are versatile precursors for the synthesis of β-aminothiols,[6] β-aminosulphonic acids,[7] and 2-iminothiazolidines,[8] present in some stereoselective catalysts, and many biologically and pharmacologically active compounds. To the best of our knowledge, only three related publications have been reported to date.[9,10] In 2013 Sala et al.[10a], and Babu and Parquette[10b] independently reported the asymmetric synthesis of β-amino-α-thiocyanate compounds via the desymmetrization of meso-aziridines with TMSNCS using combined Ca(II)/Mg(II) VAPOL phosphate salts and chiral dimeric yttrium-salen complexes as catalysts. Quite recently, Nakamura et al. also reported the same transformation using chiral imidazoline−phosphoric

Get Access
Get Access