Highly Stereoselective Synthesis of 1,3-Dienes through an Aryl to Vinyl 1,4-Palladium Migration/Heck Sequence

Pd-Catalyzed Cascade Heck/C(sp3)-H Activation for Spirocyclopropyl Oxindoles

We have demonstrated a Pd(0)-catalyzed Heck/C(sp3)-H activation cascade for the synthesis of spirocyclopropyl oxindoles in high yields from easily accessible ortho-bromoacrylamides. The formation of spirocyclopropyl oxindole is guided by an unconventional four-membered palladacycle through C(sp3)-H activation. The reaction exhibits a wide range of substrate scope and operates efficiently with a mere 0.5 mol % of Pd-catalyst. In addition, the use of microwave conditions facilitates rapid completion of the reaction. Furthermore, this spirocyclopropanation strategy can be coupled with [3 + 2] cycloaddition to produce spiropyrrolidine oxindoles, offering a valuable approach for the preparation of alkaloids such as (±)-horsfiline and (±)-coerulescine.

One-pot synthesis of multi-substituted conjugated dienones by trapping allene carbocations with active ylides

A Rh(II)/boron reagent co-catalyzed unprecedent transformation was established for the rapid construction of multi-substituted conjugated dienones under mild conditions by trapping allene carbocations with oxonium ylides from simple starting points in yields up to 85%. Two CC double bonds, one C-C and one C-O single bond were built in this one-pot reaction. The diversity-oriented strategy was also established to synthesize alkyne ether and dihydrofuran derivatives by a substrate-depended fashion.

A 1,4‐Palladium Migration/Heck Sequence with Unactivated Alkenes: Stereoselective Synthesis of Trisubstituted 1,3‐Dienes

The palladium‐catalyzed cross‐coupling of ortho‐vinyl aromatic bromides and olefins was achieved through a controllable 1,4‐palladium migration/Heck cascade protocol. The reaction represents a mild, efficient and highly stereoselective method for the synthesis of trisubstituted 1,3‐dienes, especially for triaryl‐substituted ones.

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Divergent Synthesis of Vinyl-, Benzyl-, and Borylsilanes: Aryl to Alkyl 1,5-Palladium Migration/Coupling Sequences

Organosilicon compounds have been extensively utilized both in industry and academia. Studies on the syntheses of diverse organosilanes is highly appealing. Through-space metal/hydrogen shifts allow functionalization of C-H bonds at a remote site, which are otherwise difficult to achieve. However, until now, an aryl to alkyl 1,5-palladium migration process seems to have not been presented. Reported herein is the remote olefination, arylation, and borylation of a methyl group on silicon to access diverse vinyl-, benzyl-, and borylsilanes, constituting a unique C(sp³ )-H transformation based on a 1,5-palladium migration process.

Computational study of catalyst-controlled regiodivergent pathways in hydroboration of 1,3-dienes: mechanism and origin of regioselectivity

DFT calculations were performed to elucidate the origins of catalyst-controlled regioselectivity in the hydroboration of 2-substituted 1,3-dienes.

Sequential Cross-Coupling/Annulation of ortho-Vinyl Bromobenzenes with Aromatic Bromides for the Synthesis of Polycyclic Aromatic Compounds

A sequential cross-coupling/annulation of ortho-vinyl bromobenzenes with aromatic bromides was realized, providing a direct and modular approach to access polycyclic aromatic compounds. A vinyl-coordinated palladacycle was proposed as the key intermediate for this sequential process. Excellent chemoselectivity and regioselectivity were observed in this transformation. The practicability of this method is highlighted by its broad substrate scope, excellent functional group tolerance, and rich transformations associated with the obtained products.

Applications of sulfuryl fluoride (SO2F2) in chemical transformations

A number of novel methodologies concerning the chemical, biological and medicinal applications of sulfuryl fluoride (SO₂F₂) gas have dramatically improved year by year.

SO2F2 mediated dehydrative cross-coupling of alcohols with electron-deficient olefins in DMSO using a Pd-catalyst: one-pot transformation of alcohols into 1,3-dienes

A Pd-catalyzed, SO₂F₂ mediated dehydrative cross-coupling of alcohols with electron-deficient olefins for the construction of 1,3-dienes was developed.