Catalytic C-C Cleavage/Alkyne-Carbonyl Metathesis Sequence of Cyclobutanones

Ru- and Co-Catalyzed Intermolecular Carbonyl-Alkyne Metathesis Reactions of 1H-Indene-1,2,3-triones with Internal Alkynes

The catalyst-dependent intermolecular carbonyl-alkyne metathesis (CAM) reaction of 1H-indene-1,2,3-triones with internal alkynes was realized using Ru and Co catalysts. 2-(2-Oxo-1,2-diphenylethylidene)-1H-indene-1,3(2H)-dione derivatives were obtained using a Ru catalyst, whereas S-alkyl 2-(1,3-dioxo-1,3-dihydro-2H-inden-2-ylidene)-2-phenylethanethioates were prepared using a Co catalyst. These transformations led to the synthesis of α,β-unsaturated carbonyl compounds with a broad substrate scope, excellent regiocontrol, and gram-scale amenability. This catalytic strategy using a Co or Ru catalyst has rarely been described for other established CAM catalysts.

One-Pot Dual C-C Bond-Forming Cascade Process via Suzuki Coupling and Intramolecular Cyclocondensation: An Access to Functionalized Naphthalenes

Naphthyl ketones encompass a class of essential compounds of biological and industrial significance. The development of synthetic strategies to achieve naphthyl ketones in single-step reactions from readily available materials is highly desirable. Herein, domino one-pot synthesis of functionalized naphthyl ketones via intermolecular Suzuki-Miyaura coupling, followed by intramolecular distal aldol-type condensation with the γ-methyl/methylene groups is reported. The present strategy displayed a comprehensive substrate scope and good functional group tolerance and enabled access to a variety of substituted naphthyl ketones, including aromatic-aliphatic hybrid frameworks of interesting structural features starting from the easily accessible starting materials such as α-iodoenone and 2-formylphenylboronic acids as well as 2-formylphenylboronic acid pinacol esters.

KOtBu-promoted Michael/aldol/ring-opening cascade reaction of cyclobutanones with chalcones

An efficient Michael/aldol/ring-opening cascade reaction of cyclobutanones with chalcones has been developed. This protocol employs inexpensive potassium tert-butoxide (KOtBu) as a promoter and enables an efficient synthesis of densely substituted cyclohex-3-ene-carboxylic acids in high yields with high diastereoselectivities, which are difficult to prepare through conventional approaches. The significant advantages of this methodology include transition-metal-free conditions, readily available starting materials, wide scope and high atom economy.

Photoinduced radical cascade cyclization of acetylenic acid esters with oxime esters to access cyanalkylated coumarins

A photoinduced radical cascade cyclization of acetylenic acid esters with oxime esters is described, providing cyanalkylated coumarins in superior yields under mild conditions. Radical capture and luminescence quenching experiments showed that this transformation was accomplished via a radical addition/5-exo spirocyclization/1,2-ester migration process.

Synthesis of imidazo[1,2-a]benzoazepines by alkyne-carbonyl-metathesis

Imidazo[1,2-a]benzoazepines were prepared in good yields by combination of Pd catalyzed cross coupling reactions with alkyne-carbonyl metathesis (ACM).

Palladium-catalyzed gaseous CO-free carbonylative C–C bond activation of cyclobutanones

A palladium-catalyzed carbonylative C–C bond activation reaction of cyclobutanones is reported, and it affords a variety of indanones bearing ester or amide groups using phenyl formate and benzene-1,3,5-triyl triformate as CO surrogates.