Carboboration-Driven Generation of a Silylium Ion for Vinylic C-F Bond Functionalization by B(C F ) Catalysis.

Strong main-group Lewis acids such as silylium ions are known to effectively promote heterolytic C(sp )-F bond cleavage. However, carrying out the C(sp )-F bond transformation of vinylic C-F bonds has remained an unmet challenge. Herein, we describe our development of a new and simple strategy for vinylic C-F bond transformation of α-fluorostyrenes with silyl ketene acetals catalyzed by B(C F ) under mild conditions.

Indium-Catalyzed C-F Bond Transformation through Oxymetalation/β-Fluorine Elimination to Access Fluorinated Isocoumarins.

Invited for the cover of this issue are Yoshihiro Nishimoto, Makoto Yasuda and co-workers at Osaka University and MOLSIS Inc.. The image depicts the crafting of a gladiator's shield to represent the reaction reported in this work.

Indium-Catalyzed C-F Bond Transformation through Oxymetalation/β-Fluorine Elimination to Access Fluorinated Isocoumarins.

Fluorinated heterocycles have attracted much attention in the pharmaceutical and agrochemical industries. Many strategies have already been developed to achieve the synthesis of fluorinated heterocycles. Formidable challenges remain, however, in the synthesis of fluorinated isocoumarin derivatives that are among the most alluring structural motifs.

Photoinduced Palladium-Catalyzed Carbofunctionalization of Conjugated Dienes Proceeding via Radical-Polar Crossover Scenario: 1,2-Aminoalkylation and Beyond.

A photoinduced palladium-catalyzed 1,2-carbofunctionalization of conjugated dienes has been developed. This mild modular approach, which does not require employment of exogeneous photosensitizers and external oxidants, allows for efficient and highly regio- and stereoselective synthesis of a broad range of allylic amines from readily available 1,3-dienes, alkyl iodides, and amines. Employment of O- and C-nucleophiles toward oxyalkylation and dialkylation products was also demonstrated.

Regioselective Synthesis of 5-Metalated 2-Pyrones by Intramolecular Oxymetalation of Carbonyl-ene-yne Compounds Using Indium Trihalide.

The oxyindation of carbonyl-ene-yne compounds with indium trihalides proceeded efficiently to give di-, tri-, and tetrasubstituted 2-pyrones bearing a carbon-indium bond. The metalated 2-pyrone and a zwitterion intermediate were identified by X-ray crystallographic analysis. The application of organoindium compounds to oxidation or cross-coupling provided easy access to various multifunctionalized 2-pyrones.

Selective oxymetalation of terminal alkynes 6- cyclization: mechanistic investigation and application to the efficient synthesis of 4-substituted isocoumarins.

The cyclization of heteroatom-containing alkynes with π acidic metal salts is an attractive method to prepare heterocycles because the starting materials are readily available and the organometallic compounds are useful synthetic intermediates. A new organometallic species in the heterocyclization provides an opportunity to synthesize heterocycles that are difficult to obtain. Herein, we describe a novel cyclic oxymetalation of 2-alkynylbenzoate with indium or gallium salts that proceeds with an unusual regioselectivity to give isocoumarins bearing a carbon-metal bond at the 4-position.

Indium Catalyzed Hydrofunctionalization of Styrene Derivatives Bearing a Hydroxy Group with Organosilicon Nucleophiles.

Hydrofunctionalization is one of the most important transformation reactions of alkenes. Herein, we describe the development of an indium-triiodide-catalyzed hydrofunctionalization of alkenes bearing a hydroxy group using various types of organosilicon nucleophiles. Indium triiodide was the most effective catalyst, whereas typical Lewis acids such as TiCl, AlCl, and BF·OEt were ineffective.