Palladium-catalyzed asymmetric umpolung allylation of imines with allylic alcohols

A palladium-catalyzed asymmetric umpolung allylation reaction of imines with allylic alcohols has been developed. In the presence of chiral spiro phosphoramidite ligand 4, the allylation was accomplished with high yields and good enantioselectivities. The use of highly stable and easily available allylic alcohols instead of allylic metal reagents facilitated the preparation of chiral homoallylic amines.     

Palladium-catalyzed amination of allyl alcohols

An efficient catalytic amination of aryl-substituted allylic alcohols has been developed. The complex [(η(3)-allyl)PdCl](2) modified by a bis phosphine ligand, L, has been used as catalyst in the reaction that afforded a wide range of allyl amines in good to excellent yield under mild conditions.     

Palladium-catalyzed direct allylation of fluorinated benzothiadiazoles with allyl chlorides

A palladium catalyzed cross-coupling of fluorinated benzothiadiazoles (FBTs) with allyl chlorides is reported. The significant feature of this method is synthetic simplicity, providing a straightforward access to unsymmetrical and symmetrical alkylated FBT derivatives that are of interest in organic electronic and optoelectronic materials.     

Palladium-catalyzed dehydrative allylation of hypophosphorous acid with allylic alcohols

A novel palladium-catalyzed allylation of H3PO2 with allylic alcohols is described. The phosphorus-carbon bond-forming reaction produces allylic-H-phosphinic acids and water, in the absence of additives. Primary H-phosphinic acids are obtained in excellent yields, whereas secondary H-phosphinic acids react sluggishly. A reusable polymer-supported catalyst is also described. The reaction provides an environmentally sound approach to H-phosphinic acids.     

Palladium-catalyzed allylation and deacylative allylation of 3-acetyl-2-oxindoles with allylic alcohols

The Pd-catalyzed allylation of 3-acetyl-2-oxindoles with allyl alcohol is performed using 3 mol% of Pd(dba)₂, rac-BINAP and BINOL phosphoric acid as catalytic mixture. This procedure allows the in situ synthesis of 3-allyl-2-oxindole by adding Triton B to the reaction mixture. The deacylative allylation of 3-acetyl-3-methyl-2-oxindoles with allylic alcohols is carried out with 3 mol% of Pd(OAc)₂, dppp and 1.5 equiv. of LiOtBu as base affording the corresponding 3,3-disubstituted 2-oxindoles in good yields. Both methodologies can be combined for the preparation of unsymmetrical 3,3-diallylated 2-oxindoles such as compound 7. The DaA must be carried out in the absence of oxygen in order to avoid the competitive formation of 3-alkyl-3-hydroxy-2-indoles. The later compounds can be easily obtained by deacylative oxidation of 3-alkylated 3-acetyl-2-oxindoles with LiOEt at rt under air.     

Palladium-catalyzed cross-coupling reaction: Direct allylation of aryl bromides with allyl acetate

Various aryl bromides underwent a palladium-catalyzed cross-coupling reaction with allyl acetate in the presence of hexa-n-butylditin to give the allylated products in very high yields.     

Pd-catalyzed C3-selective allylation of indoles with allyl alcohols promoted by triethylborane

Under palladium catalysis, Et3B nicely promotes allyl alcohols to undergo C3-selective allylation of indoles and tryptophan; the yields range 75-95%.     

Nickel-catalyzed allylation of allyl carbonates with homoallyl alcohols via retro-allylation providing 1,5-hexadienes

A highly efficient and mild method for the synthesis of 1,5-hexadienes, nickel-catalyzed reactions of Boc-protected allyl alcohols with homoallyl alcohols, has been developed. Nickel-mediated retro-allylation allows for the use of homoallyl alcohols as allylmetal equivalents in the synthesis of 1,5-hexadienes.     

Palladium-catalyzed allylation of acidic and less nucleophilic anilines using allylic alcohols directly

The direct activation of C-O bonds in allylic alcohols by palladium complexes has been accelerated by carrying out the reactions in the presence of titanium(IV) isoproxide and 4 A molecular sieves. The acidic and less nucleophilic anilines such as diphenylamine, phenothiazine, 4-cyanoaniline, and nitroanilines are efficiently allylated under palladium catalysis using allylic alcohols as allylating reagents.     

Palladium-catalyzed oxidation of alcohols via their allyl carbonates under neutral conditions

Treatment of alkyl allyl carbonates derived from various alcohols with a palladium catalyst in MeCN affords ketones and aldehydes in high yields. This new method of oxidation of alcohols can be applied to various alcohols except simple primary alcohols.     

Palladium-catalyzed reaction of allyl carbamates; allylation of carbonucleophiles,and protection-deprotection of amines

Allylation of carbonucleophiles with allylic carbamates under neutral conditions has been studied. The C-allylation of carbonucleophile is competitive with the N-allylation of amines, and the structure of amines is crucial for the selectivity. Bulky secondary amines gave the best results. Also a new method of protection-deprotection of amines as carbamates has been developed. Smooth deprotection is possible by the palladium-catalyzed reaction of allyl carbamates with formic acid. This method is particulary useful for primary amines, including optically active amino acids.     

Palladium-catalyzed regio- and enantio-selective allylic substitution reaction of monosubstituted allyl substrates with benzyl alcohols

Regio- and enantio-selectivities in Pd-catalyzed allylic substitution reaction of monosubstituted allylic substrates with substituted benzyl alcohols were realized, affording the corresponding products in high regioselectivity (up to 93/7) and enantioselectivity (up to 96%).     

Palladium-catalyzed electrophilic allylation reactions via bis(allyl)palladium complexes and related intermediates

The synthetic scope of the allyl-palladium chemistry can be extended to involve electrophilic reagents. The greatest challenge in these reactions is the catalytic generation of an allyl-palladium intermediate incorporating a nucleophilic allyl moiety. A vast majority of the published reactions that involve palladium-catalyzed allylation of electrophiles proceed via bis(allyl)palladium intermediates. The eta(1)-moiety of the bis(allyl)palladium intermediates reacts with electrophiles, including aldehydes, imines, or Michael acceptors. Recently, catalytic electrophilic allylations via mono-allylpalladium complexes were also presented by employment of so-called "pincer complex" catalysts.     

Triethylborane as an efficient promoter for palladium-catalyzed allylation of active methylene compounds with allyl alcohols

Without prior activation of allyl alcohols, allylation of a variety of active methylene compounds with allyl alcohols proceeds smoothly at rt-50°C in the presence of catalytic amounts of Pd(OAc)₂ (1-10 mol%), Et₃B (30-240 mol%), a phosphine ligand (1-20 mol%), and a base (0 to 50-60 mol%).     

Palladium catalyzed allylation of nitroalkanes with allyl chlorides

The palladium catalyzed synthesis of allylnitro compounds from allyl chlorides and nitroalkanes is described.

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Palladium-katalysierte Allylierung von Nitroalkanen mit Allylchlorden (Kurze Mitteilung)

Zusammenfassung Die Palladium-katalysierte Darstellung von Allylverbindungen aus Allylchloriden und Nitroalkanen wird beschrieben.

     

Palladium-catalyzed,carboxylic acid-assisted allylic substitution of carbon nucleophiles with allyl alcohols as allylating agents in water

[structure: see text] Allylic substitution of allyl alcohols in water as a suspension medium has been realized using a combination of tetrakis(triphenylphosphine)palladium and a carboxylic acid such as 1-adamantanecarboxylic acid. Various substrates turned out to be applicable to this catalytic system.     

Palladium-catalyzed silylation of alcohols with hexamethyldisilane

The combination of hexamethyldisilane and a catalytic amount of [PdCl(eta3-C3H5)]2-PPh3 was found to be effective for the trimethylsilylation of alcohols, where both of the two trimethylsilyl groups of hexamethyldisilane were transferred to alcohols without coproduction of any stoichiometric amount of byproduct but H2.