Visible-Light-Induced Catalyst-Free Carboxylation of Acylsilanes with Carbon Dioxide.

Intermolecular carbon-carbon bond formation between acylsilanes and carbon dioxide (CO) was achieved by photoirradiation under catalyst-free conditions. In this reaction, siloxycarbenes generated by photoisomerization of the acylsilanes added to the C═O bond of CO to give α-ketocarboxylates, which underwent hydrolysis to afford α-ketocarboxylic derivatives in good yields. Control experiments suggest that the generated siloxycarbene is likely to be from the singlet state (S) of the acylsilane and the addition to CO is not in a concerted manner.

Light-Mediated Carboxylation Using Carbon Dioxide.

Carbon dioxide is a green and sustainable one-carbon source, which could be utilized in the production of various fine chemicals. In recent studies, the light-mediated carboxylation employing CO has received considerable attention. The photocarboxylation of substrates with CO to build novel C-C bonds is introduced in this Minireview.

Visible-light-triggered direct keto-difluoroacetylation of styrenes with (fluorosulfonyl)difluoroacetate and dimethyl sulfoxide leads to α-difluoroacetylated ketones.

Photoredox-catalyzed direct keto-difluoroacetylation of styrenes with (fluorosulfonyl)difluoroacetate and dimethyl sulfoxide as an oxidant is disclosed. A variety of α-difluoroacetylated ketones bearing functional groups with good yields are obtained using fac-Ir(ppy)3 as a photocatalyst under visible light irradiation.

Reduction of CO with NaBH/I for the Conversion of Thiophenols to Aryl Methyl Sulfides.

We report a tandem reaction to realize reduction of carbon dioxide with thiophenols to generate aryl methyl sulfides under the NaBH/I system with 18-crown-6 as the solvent. Thiophenols bearing electron-donating and electron-withdrawing groups are feasible in this reaction. Controlled experiment results indicate that 18-crown-6 plays a critical role in six-electron reduction of carbon dioxide.

Reactions of Neutral Scandium/Phosphorus Lewis Pairs with Small Molecules.

Treating a scandium mixed alkyl/diaryloxide complex with phosphino-substituted alcohols resulted in the formation of scandium mixed alkoxyl/diaryloxide complexes Sc[OC(CH)CHPR][O-2,6- tBu-CH][THF] (6, R = Ph; 8, R = tBu). The reactivity of Sc-based Lewis pair complexes 6 and 8 toward a wide range of substrates was investigated. A ligand substitution reaction occurred when complex 6 was treated with benzophenone.