An efficient rhodium(I)-catalyzed addition of arylboronic acids to (benzyl-/arylsulfonyl)acetonitrile is described. Novel β-sulfonylvinylamine products are formed in a stereoselective fashion (Z-alkene). Upon hydrolysis, useful β-keto sulfones are obtained with a broad scope of aryl and sulfonyl substituents.
Rhodium(I)-Catalyzed Addition of Arylboronic Acids to (Benzyl-/Arylsulfonyl)acetonitriles: Efficient Synthesis of (Z)-β-Sulfonylvinylamines and β-KetoSulfones. -β-Sulfonylvinylamines (III) are formed from substrate (I) under optimized conditions A) in the presence of Cs2CO3. In the case of disubstituted sulfone (IX), this process is successful without the cesium salt and in a shorter time. If the base is omitted and the reaction is followed by conditions B), direct isolation of the ketosulfones becomes possible. Aryl substituents bearing ortho-groups are unreactive with exception of ortho-tolyl [cf. (VIIIb)]. Nitrile substrates (XI) do not react. -(TSUI, G. C.; GLENADEL, Q.; LAU, C.; LAUTENS*, M.; Org. Lett. 13 (2011) 2, 208-211, http://dx.doi.org/10.1021/ol102598p ; Davenport Res. Lab., Dep. Chem., Univ. Toronto, Toronto, Ont. M5S 3H6, Can.; Eng.) -R. Simon 15-095
A modular synthesis of highly functionalized unsymmetrical pyridines has been developed from reacting b-sulfonylvinylamines with a,b-unsaturated systems in the presence of base via the formation of 1-aza-allyl anion intermediates.
Synthesis of Unsymmetrical Polysubstituted Pyridines from β-Sulfonylvinylamines via 1-Aza-Allyl Anion Intermediates. -A modular synthesis of 2,4,6-trisubstituted pyridines is developed using the base-promoted cyclocondensation of (Z)-β-sulfonylvinylamines with chalcone-type α,β-unsaturated ketones. -(LAU, C.; TSUI, G. C.; LAUTENS*, M.; Synthesis 2011, 23, 3908-3914, http://dx.doi.org/10.1055/s-0031-1289578 ; Dep. Chem., Univ. Toronto, Toronto, Ont. M5S 3H6, Can.; Eng.) -Mais 15-143
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