60595-16-6Relevant articles and documents
Rhodium-catalyzed Sommelet-Hauser type rearrangement of α-diazoimines: Synthesis of functionalized enamides
Anbarasan, Pazhamalai,Ramachandran, Kuppan,Reddy, Angula Chandra Shekar,Reddy, Palagulla Maheswar
supporting information, p. 5649 - 5652 (2020/06/09)
An efficient rhodium catalyzed Sommelet-Hauser type rearrangement of sulfur ylides derived from α-thioesters and N-sulfonyl-1,2,3-triazoles has been successfully accomplished for the synthesis of various functionalized enamides. The developed reaction involves the unprecedented [2,3]-sigmatropic rearrangement of sulfur ylides with the imine motif. Importantly, the method works well with various substituted α-thioesters/-amides/-ketones and substituted N-sulfonyl-1,2,3-triazoles and allows the synthesis of diverse enamide derivatives in good to excellent yields. The reaction was also successfully extended to the one-pot synthesis of enamides from terminal alkynes.
Regioselective transition metal- and halogen-free direct dithiolation at C(sp3)-H of nitrotoluenes with diaryl disulfides
Kumar, Shailesh,Kadu, Rahul,Kumar, Sangit
supporting information, p. 9210 - 9214 (2016/10/13)
Here we describe a potassium tert-butoxide-mediated regioselective direct C-S bond formation at the C(sp3)-H position of nitrotoluenes with disulfides in DMSO at room temperature. The developed reaction generated, in good yields, various dithioacetals having OMe, halogen, and NH2 functionalities at various positions of the arene rings of the disulfides. Interestingly, in the absence of nitrotoluene, diaryl disulfides and diselenides underwent one-carbon homologation to form dithioacetals and diselenoacetals. Synthesized dithioacetals were transformed into 4-nitrobenzaldehyde and 7-(bis(phenylthio)methyl)-1H-indole.
Carbanion Stabilization by Adjacent Sulfur: Polarizability, Resonance, or Negative Hyperconjugation? Experimental Distinction Based on Intrinsic Rate Constants of Proton Transfer from (Phenylthio)nitromethane and 1-Nitro-2-phenylethane
Bernasconi, Claude F.,Kittredge, Kevin W.
, p. 1944 - 1953 (2007/10/03)
(Phenylthio)nitromethane, PhSCH2NO2, is about as acidic as PhCH2NO2 and about 4 pKa-units more acidic than CH3NO2 in water or aqueous DMSO, showing the well-known acidifying effect of thio substituents in the α-position of carbon acids. Over the years various interpretations have been offered for the acidifying effect of sulfur groups: d-p π-resonance, polarizability, and negative hyperconjugation. Assuming that the nature of the factors that potentially stabilize the transition state of the proton transfer from the carbon acid are the same as those that potentially stabilize the carbanion, we show that a distinction between these interpretations can be based on the effect of the phenylthio group on the intrinsic rate constants (ko) of proton transfer. Such intrinsic rate constants were determined for the deprotonation of PhSCH2NO2 and PhCH2CH2NO2 by amines in water and 90% DMSO-10% water; in both solvents ko for PhSCH2NO2 was found to be substantially higher than for PhCH2CH2NO2 as well as for other nitroalkanes reported previously. Based on a detailed analysis of how various factors such as resonance, inductive effects, polarizability, and positive and negative hyperconjugation affect the intrinsic rate constants for proton transfer, it is concluded that the high ko values for PhSCH2NO2 result from a combination of the inductive and polarizability effect of the PhS group and that d-p π-resonance and negative hyperconjugation play a minor role if any.
