Palladium-catalyzed Allylic Substitution Reactions Research Articles

Synthesis of stereodefined polysubstituted olefins. 1. Sequential intermolecular reactions involving selective, stepwise insertion of Pd(0) into allylic and vinylic halide bonds. The stereoselective synthesis of disubstituted olefins.

Palladium-catalyzed allylic substitution and cross-coupling reactions have been combined into a sequential procedure to provide a range of disubstituted olefin products starting from two-, three-, and four-carbon common olefin templates. Diverse application of this template strategy is demonstrated in a variety of model studies and in a parallel synthesis (combinatorial) approach to prepare an allylic amine molecular library. An approach toward the preparation of astaxanthin beta-D-diglucoside, an interesting antioxidant whose total synthesis has yet to be reported, using the olefin-template approach is also discussed.

Palladium-catalyzed rearrangement and substitution reactions of acyclic vinylogous carbonates and sulfonates: Development of a new leaving group for PdAllyl chemistry

Palladium-catalyzed rearrangement of the deuterium labeled vinylogous carbonate 1 furnished the β-formyl esters 3a/b in 68% yield, while the Z-vinylogous sulfonate ( Z-VINS) 2 under analogous reaction conditions led to reversible O-alkylation and isomerization to afford the E-VINS 4a/b in 61% yield. This observation prompted the development of the vinylogous sulfonate as an improved leaving group for a variety of palladium-catalyzed allylic substitution reactions.

Palladium in action: domino coupling and allylic substitution reactions for the efficient construction of complex organic molecules

The palladium-catalyzed arylation and alkenylation of alkenes, generally called the Heck reaction, has been applied to a number of new concepts. Starting from simple, oligohalogenated alkenes and arenes, the synthesis of a variety of highly functionalized carbon skeletons has been established. The domino-type combination of an intramolecular Heck with an inter- or intramolecular Diels–Alder reaction has been shown to provide facile access to interesting bicyclic and tetracyclic frameworks. While intramolecular Heck reactions on trisubstituted, cyclopropylidene-terminated alkenes proceeded with retention of the cyclopropyl moiety, tetrasubstituted alkenes with methylenecyclopropane end groups reacted with ring opening to yield cross-conjugated trienes. The study of the palladium-catalyzed oligocyclizations of 2-bromoalka-1,(ω-1)-diene- n-ynes has revealed interesting and useful systematics as to achievable ring size combinations and skeletal types. Highly functionalized methylenecyclopropanes are conveniently accessible via palladium-catalyzed allylic substitution reactions of 1-ethenylcyclopropyl sulfonates and chlorides as well as cyclopropylideneethyl esters which proceed with complete regioselectivity in most cases.

Palladium-Mediated Dynamic Kinetic Resolution: Stereoselective Synthesis of Vicinal Diamines

Can an adjacent stereocenter control selectivity in the palladium-catalyzed allylic substitution reaction? If the intermediate π-allyl palladium complex can undergo rapid inversion, the answer is yes (see reaction scheme). Starting from chiral 5-vinyloxazolidinones, trapping of intermediates 1 and 2, which are in a dynamic equilibrium, with nitrogen-containing nucleophiles leads to the quantitative formation of diamines as single diastereomers.

ChemInform Abstract: α‐Amino Esters as Nucleophiles in Diastereoselective Palladium Catalyzed Allylic Substitution Reactions.

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.

Sulfur–imine mixed donor chelate ligands for asymmetric catalysis: enantioselective allylic alkylation

A new series of sulfur–imine mixed donor chiral ligands, prepared in only two steps from commercially available ( S)-valinol, have been shown to give up to 94% enantiomeric excess in a palladium-catalysed allylic substitution reaction.

Chiral ferrocenyl-oxazolines incorporating thioether units: effective ligands for palladium-catalysed allylic substitution

The syntheses of novel ferrocene-based chiral oxazolines 17, 18 and 26 are reported. The application of these compounds as catalysts for asymmetric palladium-catalysed allylic substitution reactions has been investigated. These reactions afford the substitution products in both high yield and high enantiomeric excess. The solution electrochemical redox-behaviour of 17, 18 and 26 in the presence of palladium ions establishes that palladium coordination to the oxazoline results in a significant anodic shift in the redox potential of the ferrocene ligand. The X-ray crystal structure of the ferrocene-hydroxy amide derivative 16 is also reported.

Chiral oxazolines linked to tetrathiafulvalene (TTF): Redox-active ligands for asymmetric synthesis

The syntheses of novel tetrathiafulvalene substituted chiral oxazolines 14 and 18 are reported. The application of these compounds as catalysts for asymmetric palladium-catalysed allylic substitution reactions has been investigated along with the solution electrochemical redox behaviour of 14a in the presence of palladium ions.

ChemInform Abstract: α‐Amino Ester Derivatives as Nucleophiles in Stereoselective Palladium Catalyzed Allylic Substitution Reactions.

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.

ChemInform Abstract: α‐Aminophosphonate Derivatives as Nucleophiles in Diastereoselective and Enantioselective Palladium Catalyzed Allylic Substitution Reactions.

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.