Branched Amine Synthesis via Aziridine or Azetidine Opening with Organotrifluoroborates by Cooperative Brønsted/Lewis Acid Catalysis: An Acid-Dependent Divergent Mechanism
作者:Truong N. Nguyen、Jeremy A. May
DOI:10.1021/acs.orglett.8b01394
日期:2018.6.15
A practical catalytic method to synthesize β,β- and γ,γ-substituted amines by opening aziridines and azetidines, respectively, using alkenyl, alkynyl, or aryl/heteroaryl trifluoroborate salts is described. This reaction features simple open-flask reaction conditions, the use of transition-metal-free catalysis, complete regioselectivity, and high diastereoselectivity. Preliminary mechanistic studies
Trifluoromethylation of Disubstituted Morpholines by Metal-Free Visible Light Photoredox Catalysis
作者:Vishal Srivastava、Pravin K. Singh、Praveen P. Singh
DOI:10.14233/ajchem.2016.19893
日期:——
A mild and efficient one-pot visible light-induced method has been developed for the trifluoromethylation of disubstituted morpholines. This method includes synthesis of substituted 4-tosyl-5-[(trifluoromethyl)thio]morpholine 4(a-l) from tosylaziridine 1(a-l) and oxiran-2-thiol (2) in presence of eosin Y as an organophotoredox catalyst at room temperature under aerobic condition.
A domino Bi‐catalysedC−N/C−S bondformation of N‐sulfonylaziridines is developed with 1,4‐dithiane‐2,5‐diol to give 3,4‐dihydro‐1,4‐thiazines at room temperature. The use of Bi(OTf)3 as a catalyst, atom economy and regioselectivity are the important practical features.
Stereospecific Assembly of Fused Imidazolidines via Tandem Ring Opening/Oxidative Amination of Aziridines with Cyclic Secondary Amines Using Photoredox Catalysis
Sustainable assembly of imidazolidines is accomplished via a sequential stereospecific ringopening and C–H amination using aziridines with secondary cyclic amines under visible light mediated indazoloquinoline photoredox catalysis at ambient conditions. Optically active aziridines are coupled with high enantiomeric purities. The computational studies provide insights on the redox properties of the
Sc(III)-catalyzed domino C–C and C–N bond formation of N-sulfonyl aziridines with quinones has been accomplished to furnish functionalized indolines at a moderate temperature. The umpolung reactivity of aziridines, radical pathway, mild reaction conditions, substrate scope, and coupling of drug molecules in a postsynthetic application are the important practical features.