862776-58-7Relevant articles and documents
1,8-Diazabicyclo[5.4.0]undec-7-ene-mediated formation of N-sulfinyl imines
Ramaiah, Manjunatha M,Shubha, Priya Babu,Prabhala, Pavan Kumar,Shivananju, Nanjunda Swamy
, p. 72 - 79 (2019/12/11)
A facile and efficient method was developed for the preparation of a variety of aryl, heteroaryl, and alkyl N-sulfinyl imines using 1,8-diazabicyclo[5.4.0]undec-7-ene. In addition to tert-butanesulfinamide, the condensation is also effective with p-toluenesulfinamide. The reaction was performed at room temperature and produces the corresponding N-sulfinyl imines in excellent yields in the absence of acids, metals, and additives. This methodology is also useful for the preparation of N-sulfinyl imines on gram scale. A one-pot synthesis was developed using aryl and heteroaryl alcohols with both tert-butanesulfinamide and p-toluenesulfinamide at room temperature, resulting in the corresponding N-sulfinyl imines with good yields.
Stereoinvertive C–C Bond Formation at the Boron-Bound Stereogenic Centers through Copper-Bipyridine-Catalyzed Intramolecular Coupling of α-Aminobenzylboronic Esters
Suginome, Michinori,Yamamoto, Takeshi,Yoshinaga, Yukako
supporting information, p. 7251 - 7255 (2020/03/23)
Enantiospecific intramolecular Suzuki–Miyaura-type coupling with α-(2-halobenzoylamino)benzylboronic esters to give 3-substituted isoindolinones is achieved by using copper catalysts with 2,2′-bipyridine-based achiral ligands. Enantioenriched α-aminobenzylboron reactants bearing a hydrogen atom at the boron-bound stereogenic carbons undergo stereoinvertive coupling in the presence of a 6-phenyl-2,2′-bipyridine ligand with high enantiospecificity. α-Aminobenzylboronates bearing fully substituted boron-bound stereogenic centers also gave the 3,3-disubstituted isoindolinones with stereospecific stereochemical inversion in the presence of simple 2,2′-bipyridine as a ligand.
The effect of chiral: N-substituents with methyl or trifluoromethyl groups on the catalytic performance of mono-and bifunctional thioureas
Vazquez-Chavez, Josué,Luna-Morales, Socorro,Cruz-Aguilar, Diego A.,Díaz-Salazar, Howard,Vallejo Narváez, Wilmer E.,Silva-Gutiérrez, Rodrigo S.,Hernández-Ortega, Simón,Rocha-Rinza, Tomás,Hernández-Rodríguez, Marcos
supporting information, p. 10045 - 10051 (2019/12/23)
We evaluated thiourea organocatalysts that incorporate a chiral group which includes a trifluoromethyl moiety and contrasted their performance with non-fluorinated analogs. The comparison between such systems allows the direct study of the NH acidity of a thiourea bonded to an aliphatic substituent. In principle,-CF3 systems feature an enhanced hydrogen bond (HB) donor capacity that is undoubtedly beneficial for HB-catalysis applied to the Baylis-Hillman reaction. We found that the thiourea substituted on both nitrogens with this group accelerates this reaction like Schreiner's thiourea. On the other hand, we observed a different behavior in reactions promoted by bifunctional catalysts (thiourea-primary amine). In the Michael addition of isobutyraldehyde to methyl benzylidenepyruvate, the-CF3 containing catalysts were better than the-CH3 systems, whereas the conjugate addition to N-phenylmaleimide showed the opposite behavior. Theoretical calculations of the transition states indicated that the phenylethyl group in fluorinated and non-fluorinated compounds have different kinds of interactions with the electrophile. These interactions are responsible for a different arrangement of the electrophile and thereby the selectivity of the catalyst. Therefore, it cannot be generalized that in all cases NH acidity correlates with the performance of the catalyst, particularly, with aliphatic substituents that unlike the aromatic ones possess groups that are outside the plane of the thiourea.
