- Nickel-Catalyzed Enantioconvergent Reductive Hydroalkylation of Olefins with α-Heteroatom Phosphorus or Sulfur Alkyl Electrophiles
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Substantial advances in enantioconvergent C(sp3)-C(sp3) bond formation reactions have been made in recent years through the use of transition-metal-catalyzed cross-coupling reactions of racemic secondary alkyl electrophiles with organometallic reagents. Herein, we report a general process for the asymmetric construction of alkyl-alkyl bonds adjacent to heteroatoms, namely, a nickel-catalyzed enantioconvergent reductive hydroalkylation of olefins with α-heteroatom phosphorus or sulfur alkyl electrophiles. Including the use of readily available olefins, this reaction has considerable advantages, such as mild reaction conditions, a broad substrate scope, and good functional group compatibility, making it a desirable alternative to traditional electrophile-nucleophile cross-coupling reactions.
- Fu, Yao,He, Shi-Jiang,Li, Yan,Lu, Xi,Wang, Jia-Wang,Wang, Xiao-Xu,Xu, Zhe-Yuan
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supporting information
(2020/01/22)
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- New antifilarial agents. 1. Epoxy sulfonamides and ethynesulfonamides
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Two series of 2-substituted 1,2-epoxyethanesulfonamides 2 and ethynesulfonamides 5 were synthesized and evaluated for their antifilarial activity. The trans epoxides 2T were stereospecifically prepared by a Darzens reaction between aldehydes and halomethanesulfonamides. The cis isomers 2c were obtained from ethynesulfonamides 5 by semihydrogenation followed by KOCl epoxidation. 2-Substituted ethynesulfonamides 5 were synthesized from appropriate trans-ethenesulfonamides by a bromination/dehydrobromination sequence. These products, as well as several synthetic intermediates, were evaluated for antifilarial activity against Molinemia dessetae either in vivo in its natural host, the rodent Proechimys oris, or in vitro by a new test using cultures of the infective larvae. Most of the epoxides 2T and acetylenic derivatives 5 bearing a 2-aryl substituent were active in vitro. Among these compounds, four epoxides 2T and one acetylenic derivative 5 showed marked macrofilaricidal activity in vivo without any microfilaricidal activity. The differences between the in vivo and in vitro results may be due, in part, to the low chemical stability of the epoxy sulfonamides 2T. Despite this limitation, the activities observed in this reliable animal model suggest further development and testing of both series 2T and 5 as macrofilaricides.
- Brienne,Varech,Leclercq,Jacques,Radembino,Dessalles,Mahuzier,Gueyouche,Bories,Loiseau,Gayral
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p. 2232 - 2239
(2007/10/02)
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