Use of trichloroacetonitrile as a hydrogen chloride generator for ring-opening reactions of aziridines

Regioselective ring-opening reactions of 2-aryl-N-tosylaziridines are described, in which hydrogen chloride is generated by photodegradation of trichloroacetonitrile. HCl adducts are obtained in high yields in 1,4-dioxane, whereas methanol adducts are predominantly obtained in methanol. Trichloroacetonitrile can serve as a photoresponsive molecular storage generator for hydrogen chloride.

Aryldiazonium ion initiated C–N bond cleavage for the versatile, efficient and regioselective ring opening of aziridines

Aryldiazonium salts have been proved to initiate the regioselective cleavage of aziridines for the installation of varied functional groups.

TBD- or PS-TBD-Catalyzed One-Pot Synthesis of Cyanohydrin Carbonates and Cyanohydrin Acetates from Carbonyl Compounds

Cyanation reactions of carbonyl compounds with methyl cyanoformate or acetyl cyanide catalyzed by 5 mol % of 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) were examined. Using methyl cyanoformate, the corresponding cyanohydrin carbonates were readily obtained in high yield for aromatic and aliphatic aldehydes and ketones. Similar results were obtained when acetyl cyanide was used as the cyanide source. The polymer-supported catalyst, PS-TBD, also acted as a good catalyst for this reaction. PS-TBD was easily recovered and reused with minimal activity loss.

A Mild and Regioselective Ring-Opening of Aziridines with Acid Anhydride Using TBD or PS-TBD as a Catalyst

The ring-opening of N-tosylaziridines with various acid anhydrides catalyzed by 5 mol % of 1,5,7-triazabicyclo[4,4,0]dec-5-ene (TBD) afforded the corresponding β-amino esters in excellent yields under mild reaction conditions. Polymer-supported catalyst, PS-TBD also acts as a good catalyst for this reaction. PS-TBD was easily recovered and reused with minimal loss of activity.

Polymer-supported PPh3 as a reusable organocatalyst for the Mukaiyama aldol and Mannich reaction

Polystyrene-supported PPh₃ (PS-PPh₃) catalyzes the aldol reaction of aldehydes and imines to give the corresponding products in good to high yields.

The Ti-BINOLate-catalyzed, enantioselective ring-opening of meso-aziridines with amines

The titanium-BINOLate-catalyzed, highly enantioselective ring-opening reaction of meso-aziridines has been developed which furnishes trans-1,2-diamines in typically good yields and excellent enantioselectivities. N-Aryl aziridines attached to a 5- or 6-membered carbocyclic ring are among the best substrates for this process providing the products in up to >99% ee. The chiral catalyst is easily prepared in situ from commercially available components and does not require any laborious ligand synthesis. Structural investigations into the catalyst composition reveal an oligomeric structure of the active Ti-complex.