ChemInform Abstract: Rhodium‐Catalyzed Stereoselective Amination of Thioethers with N‐Mesyloxycarbamates: DMAP and Bis(DMAP)CH₂Cl₂ as Key Additives.

Abstract

Rhodium-Catalyzed Stereoselective Amination of Thioethers with N-Mesyloxycarbamates: DMAP and Bis(DMAP)CH 2Cl2 as Key Additives. -Chiral sulfilimines are prepared by rhodium-catalyzed intermolecular amination of thioethers with the readily available N-mesyloxycarbamate (I). DMAP and the related dimer BDC turn out to be crucial catalytic additives for improved diastereoselectivity. Cyclic voltametric measurements suggest a Rh(II)-Rh(III) complex as the catalytically active species. -(LEBEL*, H.; PIRAS, H.; BARTHOLOMEUES, J.; Angew. Chem., Int. Ed. 53 (2014) 28, 7300-7304, http://dx.

Modern Stereoselective Synthesis of Chiral Sulfinyl Compounds

“…A chiral N -mesyloxycarbamate caused a stereoselective amination of thioethers in the presence of a chiral dirhodium­(II) carboxylate catalyst to yield the corresponding sulfilimines. , The possibility of preparation of sulfoximine through oxidation of sulfilimine with NaIO 4 with RuCl 3 as a catalyst was demonstrated; removal of chiral auxiliary with zinc in acetic acid yielded NH -sulfilimine as a single enantiomer (94%). Lebel and co-workers also applied iron catalyst in a similar preparation .…”

Synthesis of Sulfinamidines and Sulfinimidate Esters by Transfer of Nitrogen to Sulfenamides

“…Regarding the synthesis of aza analogues of sulfurated compounds, the direct imination of the sulfur atom represents an interesting transformation, and important advances have been achieved over the past few years by several research groups . Most of the reported strategies for the imination of thioethers and sulfoxides involve the use of electrophilic aminating reagents, with or without metal catalysis. , Moreover, several imination strategies have been developed for the nitrogen transfer on other sulfurated compounds such as sulfenamides, sulfinamides, and thiols. ,, In continuation of our interest in the development of strategies for the electrophilic N -transfer to the sulfur atom, we became interested in the development of an efficient strategy for accessing extremely rare sulfinamidines and sulfinimidate esters. Herein, we present a robust synthetic methodology to streamline the preparation of such sulfurated motifs offering, for the first time, a widely applicable tactic, overcoming concerns related to the old procedures.…”

Catalytic Enantioselective Synthesis of Pyridyl Sulfoximines

“…Chiral sulfoximines have mostly been synthesized either from enantioenriched starting materials or by kinetic resolution of racemic sulfoximines. , The catalytic asymmetric synthesis of these compounds is still underdeveloped, with limited examples of the desymmetrizing functionalizations of pro-chiral sulfoximines . Pioneering work was achieved by the Bolm group in which a stoichiometric amount of chiral lithium amide was used to afford the product in moderate enantioselectivity (Scheme a) .…”

“…Therefore, the construction of enantioenriched pyridine derivatives has gained increased attention in the past year. , We recently reported that bis­(pyridine)­s connected to a prochiral carbon center could undergo desymmetrization through selective mono-oxidation using an aspartic acid (Asp)-peptide catalyst with excellent enantiocontrol (up to 99:1 er) . This strategy was also successfully applied to the asymmetric synthesis of helically chiral analogs of loratadine, the active ingredient of Claritin (Scheme c). , Given this result, we were curious about the performance of prochiral bis­(pyridyl)- S -centered substrates with our versatile Asp-peptide catalysts. − We decided to explore the catalytic asymmetric synthesis of sulfoximines due to the lack of successful examples in this field. − However, the long C–S bond would make it more difficult for the catalyst to differentiate the two pyridine rings, which makes the enantiocontrol a great challenge (C–S length: 1.759 Å vs C–C length: 1.520 Å; see Supporting Information, page 66) . Furthermore, the electron-withdrawing sulfoximine substituent could reduce the nucleophilicity of the pyridine nitrogen, resulting in lower reactivity.…”