Pd-Catalyzed Regio Research Articles

Palladium-Catalyzed Regio- and Diastereoselective Hydro(hetero)arylation for Rapid Construction of Quaternary Center Containing Cyclobutanes.

Herein we report a Pd-catalyzed regio- and diastereoselective hydro(hetero)arylation of inactivated alkylidenecyclobutanes. This protocol provides a rapid and atom-economical route to access 3-cyclobutyl (hetero)arenes with good functionalities toleration. With the assistance of the directing group, nucleophilic attack happened on the bulkier γ-position to form the quaternary carbon center. Furthermore, the selected products exhibited antitumor bioactivities.

Pd-Catalyzed regio- and stereoselective allylic substitution of vinylethylene carbonates with 1,2,4-triazoles.

N 1-Substituted 1,2,4-triazoles are ubiquitous skeletons in medicinal agents, agrochemicals, and organic materials. Herein, an efficient and practical method for the synthesis of N1-allylated 1,2,4-triazoles via Pd-catalyzed allylic substitution of vinylethylene carbonates (VECs) with 1,2,4-triazoles has been developed. By using a catalyst generated in situ from Pd2(dba)3·CHCl3 and DPPE under mild conditions, the process allows rapid access to N1-allylated 1,2,4-triazoles bearing diverse functionalities in high yields with excellent N1-selectivities, linear-selectivities, and Z-stereoselectivities.

Pd-Catalyzed Regio- and Enantioselective Aminoarylation of Allenols with Aryl Iodides and 2-Pyridones.

A new asymmetric catalytic protocol for the synthesis of enantioenriched N-allyl 2-pyrodones has been developed via the first Pd-catalyzed regio- and enantioselective aminoarylation of allenols with aryl iodides and 2-pyridones. By using a palladium complex generated in situ from Pd2(dba)3·CHCl3 and (S,S,S)-SKP as a catalyst, the three-component aminoarylation proceeded smoothly to afford a variety of functionalized N-allylic 2-pyridones in high yields with good regioselectivities and excellent enantioselectivities.

Pd-catalyzed Regio- and Stereoselective Hydrostannylation of an Alkyl Ethynyl Ether/One-Pot Stille Coupling Enables the Synthesis of 14-Membered Macrolactone of Luminamicin.

Regio- and stereoselective hydrostannylation of alkyl ethynyl ethers generates alkenyl ethers, which are useful building blocks in organic synthesis. This efficient synthetic method, however, is limited. Here, we report not only an efficient method for a highly regio- and stereoselective Pd-catalyzed hydrostannylation of alkyl ethynyl ethers but also a scalable synthesis and construction of the core framework of luminamicin possessing all functional groups and stereocenters.

Selective Alkynylallylation of the C−C σ Bond of Cyclopropenes

A Pd-catalyzed regio- and stereoselective alkynylallylation of a specific C-C σ bond in cyclopropenes, using allyl propiolates as both allylation and alkynylation reagents, has been achieved for the first time. By merging selective C(sp2 )-C(sp3 ) bond scission with conjunctive cross-couplings, this decarboxylative reorganization reaction features fascinating atom and step economy and provides an efficient approach to highly functionalized dienynes from readily available substrates. Without further optimization, gram-scale products can be easily obtained by such a simple, neutral, and low-cost catalytic system with high TONs. DFT calculations afford a rationale toward the formation of the products and indicate that the selective insertion of the double bond of cyclopropenes into the C-Pd bond of ambidentate Pd complex and the subsequent nonclassical β-C elimination promoted by 1,4-palladium migration are critical for the success of the reaction.

Asymmetric Allylic Etherification of Vinylethylene Carbonates with Diols via Pd/B Cooperative Catalysis: A Route to Chiral Hemi-Crown Ethers.

Pd-catalyzed regio- and enantioselective allylic etherification of vinylethylene carbonates (VECs) with diols has been developed. By using cooperative catalysts of the chiral palladium complex and triethylborane in mild conditions, the process gave monoetherified and bisetherified polyglycol derivatives with tetrasubstituted stereocenters in high yields with complete regioselectivities and high levels of enantio- and diastereoselectivities.

Pd-Catalyzed regio- and enantioselective allylic substitution with 2-pyridones.

An efficient method for the asymmetric synthesis of N-substituted 2-pyridones via Pd-catalyzed regio- and enantioselective allylic substitution of hydroxyl-containing allylic carbonates with 2-pyridones has been developed. By using a palladium complex in situ generated from Pd2(dba)3·CHCl3 and phosphoramidite L2 as a ligand, the process allowed rapid access to N-substituted 2-pyridones with complete chemo- and regioselectivities and good to high enantioselectivities.

Palladium-catalyzed regio- and enantioselective hydroesterification of aryl olefins with CO gas

An effective Pd-catalyzed regio- and enantioselective hydroesterification of aryl olefins with CO gas is described.

Pd-Catalyzed Regio- and Stereoselective C-Nucleoside Synthesis from Unactivated Uracils and Pyranoid Glycals.

Pd-catalyzed regio- and stereoselective C-nucleoside synthesis from pyranoid glycals and unactivated N,N-dialkyluracils is described. Depending upon the reaction conditions, either β-hydride or β-heteroatom eliminated C-nucleosides were obtained exclusively. Different glycals with various protecting groups reacted smoothly. Mechanistically, uracil first undergoes electrophilic palladation regioselectively at the C-5 position to generate the active organopalladium species, which then attacks the glycal in a regio- and stereoselective mode to generate C-nucleosides. The method obviates the use of heavy metals such as mercury or preactivation of protected uracils, making it an attractive strategy for C-nucleoside synthesis.

Palladium-Catalyzed Highly Regio- and Enantioselective Hydroesterification of Aryl Olefins with Phenyl Formate.

An effective Pd-catalyzed regio- and enantioselective hydroesterification of aryl olefins with phenyl formate is described. A variety of phenyl 2-arylpropanoates can be obtained in good yields with high b/l ratios and ee's without using toxic CO gas.

Pd-catalyzed regio- and stereoselective addition of boronic acids to silylacetylenes: a stereodivergent assembly of β,β-disubstituted alkenylsilanes and alkenyl halides.

An efficient Pd-catalyzed addition of boronic acids to silylacetylenes is described, providing β,β-disubstituted (E)- or (Z)-alkenylsilanes in satisfactory yields with excellent regio- and stereoselectivity under mild reaction conditions. It represents the first highly regio- and stereoselective addition of boronic acids to aryl and alkenyl silylacetylenes. Moreover, the sequential Pd-catalyzed boron addition/N-halosuccinimide-mediated halodesilylation reaction results in a stereodivergent approach to β,β-disubstituted alkenyl halides, which can serve as versatile synthetic intermediates for the stereodivergent assembly of (E)- and (Z)-trisubstituted alkenes via transition-metal-catalyzed cross-coupling reactions.

Pd-Catalyzed Regio- and Stereoselective Hydrosilylation of Alkynes

Pd-Catalyzed Regio- and Stereoselective Hydrosilylation of Alkynes

Palladium‐Catalyzed Carbocyclization of Alkynyl Ketones Proceeding through a Carbopalladation Pathway

Palladium‐Catalyzed Carbocyclization of Alkynyl Ketones Proceeding through a Carbopalladation Pathway

Pd-catalyzed regio and stereocontrolled mono and bis-coupling reactions of 1-bromo-6-chlorohexa-1,3,5-triene: synthesis of a naturally occurring tetraenynone

The synthesis of new 1,6-dihalogenohexatrienes is described. The chemoselectivity of pallado-catalyzed cross-coupling reaction is studied and a short synthesis, by Negishi and Sonogashira reactions, of a natural product is described.

Pd-Catalyzed Regio- and Stereoselective Cyclization−Heck Reaction of Monoesters of 1,2-Allenyl Phosphonic Acids with Alkenes

[reaction: see text] The cyclization-Heck reactions of monoesters of 1, 2-allenyl phosphonic acids with alkenes were studied. The reaction afforded 4-(1-Z-alkenyl)-2-ethoxy-2,5-dihydro[1,2]oxaphosphole 2-oxides regio- and stereoselectively. Pd(II) was regenerated from the in situ formed Pd(0) using CaH2(cat.)/NaI/O2 or benzoquinone to furnish the catalytic cycle.

Palladium-Catalyzed Ring Opening of Isoprene Monoxide with Nitrogen Nucleophiles - Asymmetric Synthesis of Branched Amino Sugars

The Pd-catalyzed regio- and enantioselective ring opening of isoprene monoxide with primary amines as pronucleophiles is developed with good yield and enantioselectivity, constructing a quaternary stereocenter enantioselectively. This methodology was used as the chirality inducing key step in the asymmetric synthesis of vancosamine derivative 19. The synthesis was achieved in 9 total steps and 28.6% overall yield.

New Aspects in the Stereoselective Ethynylation of β‐C‐Glycoside Aldehydes. Application to the Synthesis of an Ambruticin Fragment.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Facile Oxidative Addition of the Phosphorous−Selenium Bond to Pd(0) and Pt(0) Complexes and Development of Pd-Catalyzed Regio- and Stereoselective Selenophosphorylation of Alkynes

Facile Oxidative Addition of the Phosphorous−Selenium Bond to Pd(0) and Pt(0) Complexes and Development of Pd-Catalyzed Regio- and Stereoselective Selenophosphorylation of Alkynes

ChemInform Abstract: Pd‐Catalyzed Regio‐ and Stereoselective Carboxylation of Cycloalkanes with CO.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.