66898-04-2Relevant academic research and scientific papers
Directed Ortho metalation-cross coupling strategies. N-cumyl arylsulfonamides. Facile deprotection and expedient route to 7- and 4,7-substituted saccharins
Blanchet, Jerome,Macklin, Todd,Ang, Patrick,Metallinos, Costa,Snieckus, Victor
, p. 3199 - 3206 (2008/02/04)
(Chemical Equation Presented) By using the powerful N-cumylsulfonamide directed metalation group (DMG), a series of 2-substituted derivatives were prepared according to the directed ortho metalation (DoM) tactic (Table 1). Mild conditions for N-decumylation and other simple transformations of the products have been achieved (Scheme 2). The 3-silyloxy sultam 12 undergoes further DoM to give formyl, thiomethyl, iodo, and amide derivatives 13a-g of potential value for saccharin synthesis (Table 2). An effective route to target 7-aryl saccharins via Suzuki cross coupling (Table 3) followed by further metalation-carbamoylation and cyclization (Table 5) is described. 4,7-Disubstituted saccharins have been obtained by similar sequences (Scheme 3). Mild TFA-mediated N-decumylation furnishes substituted primary arylsulfonamides (Table 4).
Imido transfer from bis(imido)ruthenium(VI) porphyrins to hydrocarbons: Effect of imido substituents, C-H bond dissociation energies, and Ru VI/V reduction potentials
Leung, Sarana Ka-Yan,Tsui, Wai-Man,Huang, Jie-Sheng,Che, Chi-Ming,Liang, Jiang-Lin,Zhu, Nianyong
, p. 16629 - 16640 (2007/10/03)
[RuVI(TMP)(NSO2R)2] (SO2R = Ms, Ts, Bs, Cs, Ns; R = p-C6H4OMe, p-C6H 4Me, C6H5, p-C6H4-Cl, p-C6H4NO2, respectively) and [Ru VI(Por)(NTs)2] (Por = 2,6-Cl2TPP, F 20-TPP) were prepared by the reactions of [RuII(Por)(CO)] with Phl=NSO2R in CH2Cl2. These complexes exhibit reversible RuVI/V couple with E1/2 = -0.41 to -0.12 V vs Cp2Fe+/10 and undergo imido transfer reactions with styrenes, norbornene, cis-cyclooctene, indene, ethylbenzenes, cumene, 9,10-dihydroanthracene, xanthene, cyclohexene, toluene, and tetrahydrofuran to afford aziridines or amides in up to 85% yields. The second-order rate constants (k2) of the aziridination/amidation reactions at 298 K were determined to be (2.6 ± 0.1) × 10-5 to 14.4 ± 0.6 dm3 mol-1 s-1, which generally increase with increasing RuVI/V reduction potential of the imido complexes and decreasing C-H bond dissociation energy (BDE) of the hydrocarbons. A linear correlation was observed between log K (K is the k2 value divided by the number of reactive hydrogens) and BDE and between log k2 and E1/2(RuVI/V); the linearity in the former case supports a H-atom abstraction mechanism. The amidation by [RuVI(TMP)(NNs) 2] reverses the thermodynamic reactivity order cumene > ethylbenzene/toluene, with K(3° C-H)/K(2° C-H) = 0.2 and K(3° C-H)/K(1° C-H) = 0.8.
