The Dinosyl Group: A Powerful Activator for the Regioselective Alcoholysis of Aziridines

Abstract

The N-2,4-dinitrophenylsulfonyl group (dinosyl, DNs) was found to be an excellent choice for the N-activation of aziridines towards ring cleavage with primary, secondary, and sterically demanding tertiary alcohols. Alcoholysis does not need any additional catalyst and is regioselective for the less-

Competitive Copolymerization: Access to Aziridine Copolymers with Adjustable Gradient Strengths

“…Such findings are supported by the data from Stanetty and co-workers, who reported on dinosyl-activated aziridines that ring-opened rapidly in the presence of alcohols. 52 As Figure S1B,D illustrates, the N−S bond distance shortens systematically, which correlates with the explanations that the free electron pair of the nitrogen compensated the electron loss on the sulfur caused by the activation group. The natural charge at the electropositive carbon in Figure S1C,E represents the electrophilicity of the 3-positioned carbon caused by the EWD nature of the activation groups, with very reactive monomers having a higher natural charge.…”

“…The nitrosyl monomers prepared by Rupar et al are an example of such highly reactive sulfonyl aziridines as they spontaneously ring-opened. Such findings are supported by the data from Stanetty and co-workers, who reported on dinosyl-activated aziridines that ring-opened rapidly in the presence of alcohols . As Figure S1B,D illustrates, the N–S bond distance shortens systematically, which correlates with the explanations that the free electron pair of the nitrogen compensated the electron loss on the sulfur caused by the activation group.…”

Stereoselective Synthesis of 1,2‐trans‐Diamines Using the Three‐Component Borono‐Mannich Condensation – Reaction Scope and Mechanistic Insights

“…The solvent was evaporated, the residue was distributed between MTBE (15 mL) and water (5 mL), and the combined organic layers were washed with NaHCO 3 (10 mL), brine (10 mL), and Na 2 SO 4 . The concentration of the solvent led to the precipitation of pure 3d , which was collected by filtration (378 mg, 43 %, the NMR spectroscopic data were consistent with those reported previously) . General Procedure (A) was followed with alcohol 3d (184 mg, 0.48 mmol), TEMPO (4 mg, 0.024 mmol), KBr (57 mg, 0.48 mmol), NaOCl (2 mL, 0.5 m , 0.96 mmol), and saturated aqueous NaHCO 3 (5 mL) in CH 2 Cl 2 (10 mL).…”

“…The tert ‐butoxycarbonyl (Boc) derivative 7h was prepared directly from the commercially available N ‐( tert ‐butoxycarbonyl)‐ l ‐phenylalanine through the reduction of the acid with BH 3 · THF and oxidation of 3h with TEMPO–NaOCl. The 2,4‐dinitrophenylsulfonamide (DNs) compound 7d was prepared through the sulfonylation of l ‐2‐amino‐3‐phenyl‐1‐propanol and classical oxidation to the corresponding aldehyde. For the aldehyde 7g with the triflate (Tf) protecting group, oxidation was performed with the Dess–Martin periodinane (DMP), which gave a cleaner reaction than that with TEMPO–NaOCl.…”

Nucleophilic Aliphatic Substitution

“…70 In fact, a quantitative yield of the β-amino ether is obtained in a few hours at 65 • C. The reaction occurs with primary, secondary, and tertiary alcohols, with regioselectivity between 87 : 13 and >99 : 1 at the leastsubstituted carbon. Regioselectivity is greater when a more sterically hindered alcohol is used.…”