- Rh(III)-Catalyzed Oxidative Annulation of Sulfoximines with Arylalkynyl Silanes via Desilylation
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Rh(III) catalyzed oxidative synthesis of 1,2-benzothiazine derivatives using sulfoximine as a directing group under C-H activation strategy is reported. In this study, we utilized arylalkynyl silanes as an alternate for terminal alkynes to obtain the 1,2-
- Hanchate, Vinayak,Muniraj, Nachimuthu,Prabhu, Kandikere Ramaiah
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- Enantioconvergent Cu-Catalyzed Radical C-N Coupling of Racemic Secondary Alkyl Halides to Access α-Chiral Primary Amines
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α-Chiral alkyl primary amines are virtually universal synthetic precursors for all other α-chiral N-containing compounds ubiquitous in biological, pharmaceutical, and material sciences. The enantioselective amination of common alkyl halides with ammonia is appealing for potential rapid access to α-chiral primary amines, but has hitherto remained rare due to the multifaceted difficulties in using ammonia and the underdeveloped C(sp3)-N coupling. Here we demonstrate sulfoximines as excellent ammonia surrogates for enantioconvergent radical C-N coupling with diverse racemic secondary alkyl halides (>60 examples) by copper catalysis under mild thermal conditions. The reaction efficiently provides highly enantioenrichedN-alkyl sulfoximines (up to 99% yield and >99% ee) featuring secondary benzyl, propargyl, α-carbonyl alkyl, and α-cyano alkyl stereocenters. In addition, we have converted the masked α-chiral primary amines thus obtained to various synthetic building blocks, ligands, and drugs possessing α-chiral N-functionalities, such as carbamate, carboxylamide, secondary and tertiary amine, and oxazoline, with commonly seen α-substitution patterns. These results shine light on the potential of enantioconvergent radical cross-coupling as a general chiral carbon-heteroatom formation strategy.
- Cheng, Jiang-Tao,Dong, Xiao-Yang,Gu, Qiang-Shuai,Li, Zhong-Liang,Liu, Juan,Liu, Xin-Yuan,Luan, Cheng,Wang, Fu-Li,Wang, Li-Lei,Yang, Ning-Yuan,Zhang, Yu-Feng
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supporting information
p. 15413 - 15419
(2021/09/30)
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- Enantioselective Synthesis of Chiral-at-Sulfur 1,2-Benzothiazines by CpxRhIII-Catalyzed C?H Functionalization of Sulfoximines
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Sulfoximines with stereogenic sulfur atoms are attractive structural motifs in drug discovery. A direct catalytic enantioselective method for the synthesis of sulfur-chiral 1,2-benzothiazines from readily accessible diaryl sulfoximines is presented. Rhodium(III) complexes equipped with chiral cyclopentadienyl ligands and paired with suitable carboxylic acid additives engage in an enantiodetermining C?H activation directed by the sulfoximine group. Subsequent trapping of the rhodacycle with a broad range of diazoketones gives access to S-chiral 1,2-benzothiazines with synthetically highly attractive substitution patterns in good yields and enantioselectivities.
- Sun, Yang,Cramer, Nicolai
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p. 15539 - 15543
(2018/11/02)
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- Rhodium(III)-Catalyzed C?H Alkynylation of N-Methylsulfoximines
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A rhodium(III)-catalyzed direct C?H alkynylation of a wide range of N-methylsulfoximines with (bromoethynyl)triisopropylsilane has been developed. This protocol is compatible with both (S,S)-diaryl sulfoximines and (S,S)-alkyl aryl sulfoximines, and shows mild conditions, and good functional group tolerance. The synthetic utility of this method has been demonstrated by subsequent various transformations of the products.
- Wang, Tao,Wang, Yi-Ning,Wang, Rui,Wang, Xi-Sheng
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supporting information
p. 2449 - 2452
(2018/08/17)
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