Palladium-Catalyzed Skeletal Reorganization of Cyclobutanones Invoving Successive C—C Bond/C—H Bond Cleavage

The utilization of cyclobutanones as the synthon in transition metal catalysis has been made great success.Because C(carbonyl)−C bond of cyclobutanones can be cleaved through strain release.Despite those advancements,the main catalysts in literature are Rh catalysts or Ni catalysts and the reaction with C—H bond is still underdeveloped.Herein,we realized the first palladium-catalyzed skeletal reorganization of cyclobutanones involving successive cleavage of C(carbonyl)−C bonds and C—H bond cleavage,which constitutes an rapid access to diverse indanones.In contrast to the previous Rh-catalytic system,the Pd-catalytic system herein involves different mechanism and features several advantages:1)no need of directing group to facilitate the C(carbonyl)−C bond cleavage;2)much milder reaction condition and 3)simplified work-up.

Ir-Catalyzed Asymmetric Hydrogenation of α-Alkylidene β-Lactams and Cyclobutanones

Chiral β-Iactams and cyclobutanones are present in numerous natural and pharmaceutical products. The stereoselective construction of chiral four-membered cyclic compounds is an ongoing challenge for the chemical community. Herein, we report a highly stereocontrolled construction of four-membered ring （mini-sized） β-lactams and cyclobutanones via an Ir/In-BiphPHOX-catalyzed asymmetric hydrogenation, providing the corresponding optically active four-membered ring carbonyl products bearing an α-chiral carbon center with excellent yields （up to 99%） and enantioselectivities （up to 98%） under mild reaction conditions （1.0-2.5 bar H2 for 1.0-10 h）. The reaction presents wide substrate scope. Diverse transformations of the catalyzed products were also conducted to show the potential utility of this protocol.

Iron-catalyzed cyanoalkylation of difluoroenol silyl ethers with cyclobutanone oxime esters

An iron-catalyzed coupling reaction of difluoroenol silyl ethers and cyclobutanone oxime esters is described. This protocol provides a convenient access to various previously unknown and potentially useful gem-difluoromethylenated ketonitriles inmoderate to good yields. The transformations of resulting products to other fluorinecontaining products is also documented.