α‐Thianthrenium Carbonyl Species: The Equivalent of an α‐Carbonyl Carbocation

Abstract

Here we report an α-thianthrenium carbonyl species, as the equivalent of an α-carbonyl carbocation, which is generated by the radical conjugate addition of a trifluoromethyl thianthrenium salt to Michael acceptors. The reactivity allows for the synthesis of C α -tetrasubstituted α-and β-amino acid analogues via a Ritter reaction by addition of acetonitrile. Addition of hydroxide, methoxide, and even fluoride can afford αheteroatom substituted α-phenylpropanoates.

Transition-metal-free C–S bond cleavage and transformation of organosulfur compounds

“…Later, the Ritter group developed a visible-light-induced radical addition reaction of trifluoromethyl thianthrenium salt, acrylates, and acetonitrile (Scheme 30b). 80 Similar to Patureaua's work, both CF 3 radical 26C and TT + are generated from the trifluoromethyl thianthrenium salt 161 via a photo-irradiated C-S bond cleavage. Furthermore, a-arylsubstituted acrylates 162 can produce aamino acid derivatives 164, while b-amino acid derivatives 165 can be obtained from a-benzylsubstituted acrylates 163.…”

“…74 After that, significant progress has been made in the last five years. [75][76][77][78][79][80][81][82][83][84][85][86][87][88][89] Although several related reviews have been reported by Ritter, 76 Wang, 77 and Shu, 78 no comprehensive review on the transition-metal-free transformations has been published to date.…”

One-step synthesis of polycyclic thianthrenes from unfunctionalized aromatics by thia-APEX reactions

“…128°, whereas it reversibly transforms into a planar structure in the radical cation state. 1 c ,2 The redox behavior and cationic-state capability of thianthrene can be utilized for supramolecular chemistry 2 a ,3 and development of organic chemical reactions 4 and cathode materials. 5 Moreover, the thianthrene structure is favorable for electron-donation and intersystem crossing due to the electron-richness and heavy atom effect of sulfur atoms.…”

“…6 By utilizing these functionalities, π-extended thianthrenes have been developed in recent years. 3–7 Fig. 1B shows the representative thianthrene-based materials with unique reactivities and optoelectronic and supramolecular properties: room-temperature phosphorescence (compound A ), 6 d thermally activated delayed fluorescence (TADF) (compound B ), 6 d C–H functionalization of aromatic compounds (compound C ), 4 semiconductivity (compound D ), 7 l and host–guest capability for fullerenes (compound E ).…”

Visible Light Promotes Cascade Trifluoromethylation/Cyclization, Leading to Trifluoromethylated Polycyclic Quinazolinones, Benzimidazoles and Indoles

“…To address this question, cost-effective and readily available trifluoroacetic acid (TFA), trifluoroacetic anhydride (TFAA) and triflic anhydride (Tf 2 O) have recently been investigated as trifluoromethylation reagents under diverse catalysis by Zhang, Stephenson, Qing and Ritter, etc. [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 ].…”