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A rhodium-catalyzed olefination of aliphatic aldehydes with arylboroxines is described. The simple rhodium(I) complex [Rh(cod)OH]2without any external ligands or additives is able to catalyze the reaction in air and neutral conditions, allowing the construction of aryl olefins in an efficient manner with a good functional group tolerance. The mechanistic investigation illustrates that the binary rhodium catalysis is the key for the transformation, which involves a Rh(I)-catalyzed 1,2-addition and a Rh(III)-catalyzed elimination.

A palladium-catalyzed cross-coupling reaction of cyclobutenone N-tosylhadrazones with organohalides is disclosed. The protocol involves the generation of a strained allylpalladium intermediate from readily available starting materials through palladium carbene migratory insertion, which undergoes electrocyclic ring opening and β-hydride elimination for the production of conjugated enynes and enallenes. The broad substrate scope, good to excellent yields, and tunable product diversity make the protocol potentially useful in organic synthesis.

The exploration of the reactivity of gem-difluorinated small-size rings has continuously drawn attention in recent years but is limited to three-membered carbocycles. Herein we report a copper-catalyzed reaction of gem-fluorinated cyclobutenes with bis(pinacolato)diboron (B2pin2). A sequence of defluoroborylation and a ring-opening process produces B,F-bifunctional 1,3-dienes in a stereoselective manner. The transformation together with the efficient downstream coupling of the boronate and the fluoride moieties collectively constitutes a modular route to highly functionalized and stereocontrolled 1,3-dienes.

Olefination of carbonyl compounds is a typical strategy for the synthesis of olefins. Herein, we reported a rhodium‐catalyzed cross‐coupling reaction of ketones with arylboroxines for straightforward access of olefins. The reaction displays a good functional group tolerance and affords the corresponding products in good to excellent yields. Addition and elimination are suggested as the indispensable steps in catalytic cycle by preliminary mechanistic experiments. This reaction provided a complementary method in catalytic construction of olefins from ketones and organoboron compounds. A rhodium‐catalyzed olefination of ketones with arylboroxines has been developed. The transformation is realized by rhodium‐catalyzed 1,2‐addition of arylboroxines to ketones and arylboroxine‐promoted dehydration of tertiary alcohols. The reaction proceeds under simple reaction conditions, affording olefins in a straightforward manner with good to excellent yields.

An efficient protocol for the asymmetric hydroarylation and hydroalkenylation of benzo[b]thiophene 1,1-dioxides with organoboranes has been developed. The combination of a rhodium(I) precatalyst and a chiral diene ligand constitutes the catalytic system, which enables the facile synthesis of 2,3-dihydrobenzo[b]thiophene 1,1-dioxides in good yields with high enantioselectivities. The merging of this asymmetric hydroarylation with the downstream alkylations delivers 2,3-dihydrobenzo[b]thiophene 1,1-dioxides that contain two continuous quaternary stereocenters with high enantioselectivities in a diastereodivergent manner.

Transition-metal-catalyzed C-H bond activation represents one of the most attractive research areas in organic synthesis. In contrast to the great developments made in directed C-H bond functionalization of arenes, the directing group-assisted activation of non-aromatic vinylic C-H bonds still remains challenging. During the recent years, significant progress has been made in this fascinating field with various functionalized alkenes, heterocycles and carbocycles being obtained. This article will focus on the recent achievements in the field of directing-group-assisted vinylic C-H bond functionalization.

Described herein are the palladium-catalyzed cross-coupling reactions of cyclobutanone-derived N-sulfonylhydrazones with aryl or benzyl halides, suggesting that the metal carbene process and β-hydride elimination can smoothly occur in strained ring systems. Structurally diversified products including cyclobutenes, methylenecyclobutanes, and conjugated dienes are selectively afforded in good to excellent yields. Preliminary success in asymmetric carbene coupling reactions in strained ring systems has been achieved, providing a promising route for the synthesis of enantioenriched four-membered-ring molecules.