Visible-Light-Driven Carboxylative 1,2-Difunctionalization of C=C Bonds with Tetrabutylammonium Oxalate.

Herein, we report a visible-light-induced charge-transfer-complex-enabled dicarboxylation and deuterocarboxylation of C=C bonds with oxalate as a masked CO source under catalyst-free conditions. In this reaction, we disclosed the first example that the tetrabutylammonium oxalate could be able to aggregate with aryl substrates via π-cation interactions to form the charge transfer complexes, which subsequently triggers the single electron transfer from the oxalic dianion to the ammonium countercation under irradiation of 450 nm bule LEDs, releasing CO and CO radical anions. Diverse alkenes, dienes, trienes, and indoles, including challenging trisubstituted olefins, underwent dicarboxylation and anti-Markovnikov deuterocarboxylation with high selectivity to access valuable 1,2- and 1,4-dicarboxylic acids as well as indoline-derived diacids and β-deuterocarboxylic acids under mild conditions.

Photoinduced Radical Approach for Desulfurative Alkylation of Cysteine Derivatives to Make Unnatural Amino Acids.

Unnatural amino acids (UAAs) are highly valuable molecules in organic synthesis, pharmaceutical sciences, and material science. Herein, we present a photocatalytic radical approach for desulfurative alkylation of cysteine derivatives with arenethiol as the hydrogen atom transfer catalyst for making UAAs and peptides. The formate salt, acting as the hydrogen atom donor, in situ generates the highly reductive CO radical anion species, which is the key to unlocking the C-S bond cleavage process with a simple benzoyl protecting group.

Formate and CO Enable Reductive Carboxylation of Imines: Synthesis of Unnatural α-Amino Acids.

Herein, a photocatalytic umpolung strategy for reductive carboxylation of imines for the synthesis of α-amino acids was disclosed. Carbon dioxide radical anion (CO) generated from formate is the key single electron reductant in the reactions. An unprecedentedly broad substrate scope of imines with excellent reaction yields was obtained with carbon dioxide (CO) and formate salt as carbon sources.

Dinuclear cobalt and nickel complexes of a mercaptoacetic acid substituted 1,2,4-triazole ligand: syntheses, structures and urease inhibitory studies.

Because of its versatile coordination modes and strong coordination ability, the mercaptoacetic acid substituted 1,2,4-triazole 2-{[5-(pyridin-2-yl)-4H-1,2,4-triazol-3-yl]sulfanyl}acetic acid (HL) was synthesized and characterized. Treatment of HL with cobalt and nickel acetate afforded the dinuclear complexes {μ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κN,N:N,O}bis[aqua(methanol-κO)cobalt(II)] methanol disolvate, [Co(CHNOS)(CHOH)(HO)]·2CHOH (1), and {μ-3-[(carboxylatomethyl)sulfanyl]-5-(pyridin-2-yl)-4H-1,2,4-triazol-4-ido-κN,N:N,O}bis[diaquanickel(II)] methanol disolvate dihydrate, [Ni(CHNOS)(HO)]·2CHOH·2HO (2), respectively. Complex 1 crystallized in the monoclinic space group P2/c, while 2 crystallized in the tetragonal space group I4/a.

The genus Duda part II: the species group from East Asia, with morphological and molecular evidence (Diptera, Drosophilidae).

Eight new species of the species group are described from China: , , , , , , , and One known species S. c (Kikkawa & Peng) is redescribed. A key to all the examined species in the group is provided.

The genus Duda part I: the species group from the Oriental Region, with morphological and molecular evidence (Diptera, Drosophilidae).

Seven new species of the species group are described from east Asia: , , , , , and Three known species, (Tsacas & Chassagnard), (Tsacas & Chassagnard) and (Duda) are redescribed. A key to all the examined species in the group is provided. Species delimitations have been improved by integrating the DNA sequences with morphological information.