Concise syntheses of nonracemic gamma-fluoroalkylated allylic alcohols and amines via an enantiospecific palladium-catalyzed allylic substitution reaction

Green protocols for Tsuji–Trost allylation: an overview

Since its inception in 1960s, the Tsuji–Trost reaction, an allylic substitution reaction with diverse nucleophiles such as phenols, amines, thiols, and active methylene compounds, has remained as one of the most useful and widely used organic reactions for the construction of C–C and C–heteroatom bonds. Allylic compounds such as allylic acetates, alcohols, halides, and carbonates undergo this transformation which plays an important role in the total synthesis of various natural products. The competence to incorporate synthetically demanding allylic functionalities makes it a beneficial tool for the synthesis of complex molecules. Over the last two decades, major advancements for this unique and facile Tsuji–Trost allylation reaction have been made with special emphasis to develop greener and sustainable protocols. This chapter presents an update on the significant progress focusing on the newly designed catalytic systems with high efficiency, the use of eco-friendly solvents or solvent-free conditions, low or room temperature conditions and waste management, along with future outlook.

Synthesis of 1-(Difluoromethyl)alk-1-enes via Palladium-Catalyzed SN2'-Type Substitution Reaction of Difluoromethylated Allylic Phosphates with 1,3-Dicarbonyl Compounds and Imides

Herein, we report the synthesis of 1-(difluoromethyl)alkenes via a palladium-catalyzed reaction of difluoromethyl-substituted allylic phosphates with 1,3-dicarbonyl compounds using PdCl₂(PPh₃)₂ as a precatalyst. 1,3-Dicarbonyl compounds attacked the γ-carbon with respect to the difluoromethyl group to afford their corresponding S_N2'-type substitution products irrespective of the substitution pattern in the allylic phosphates. This regioselectivity has been ascribed to the electronic environment of the unsymmetrical π-allylpalladium intermediate using density functional theory (DFT) calculations. The reaction of difluoromethyl-substituted allylic phosphates with imides was also carried out using a different catalyst system composed of [PdCl(η³-allyl)]₂ and di(diphenylphosphino)butane (dppb).

Ruthenium-catalyzed regioselective allylic amination of 2,3,3-trifluoroallylic carbonates

We demonstrated the ruthenium-catalyzed allylic amination of 2,3,3-trifluoroallylic carbonates with several types of amines. The reactions proceeded with several types of amines, and succeeded in obtaining polyfluorinated terminal alkenes possessing branched allylic amines as a single regioisomer.

Recent advances in the Overman rearrangement: synthesis of natural products and valuable compounds

This review documents the reports since 2005 on the Overman rearrangement, an important C–N bond forming reaction that has been profoundly used in the synthesis of natural products, synthetic intermediates, building blocks and valuable compounds.

Palladium-catalyzed enantioselective allylic alkylation of trifluoromethyl group substituted racemic and acyclic unsymmetrical 1,3-disubstituted allylic esters with malonate anions

We accomplished the enantioselective allylic alkylation of racemic and acyclic unsymmetrical 1,3-disubstituted allylic esters with a malonate anion by DYKAT.

Polymeric β-alanine incarcerated Pd(ii) catalyzed allylic etherification in water: a mild and efficient method for the formation of C(sp3)–O bonds

A new heterogeneous palladium(ii) catalyst has been developed through a convenient and economic way for the synthesis of allyl-aryl ether.

Understanding the mechanism of Pd-catalyzed allylic substitution of the cyclic difluorinated carbonates

We present a mechanistic investigation of Pd-catalyzed allylic substitution of cyclic gem-difluorinated carbonates 1 and 4, previously employed in the synthesis of 3',3'-difluoro-2'-hydroxymethyl-4',5'-unsaturated carbocyclic nucleosides in 17 steps. The substitution features a reversal of regioselectivity caused by fluorine.

Ruthenium-catalyzed stereospecific decarboxylative allylation of non-stabilized ketone enolates

The ruthenium-catalyzed stereospecific decarboxylative allylation of ketone enolates provides access to gamma,delta-unsaturated ketones with good yields and enantio-enrichments.

Allylation of Alcohols and Carboxylic Acids with Allyl Acetate Catalyzed by [Ir(cod)2]+BF4- Complex

A facile method for the synthesis of allyl alkyl ethers from alcohols with allyl acetate was developed by the use of [Ir(cod)(2)](+)BF(4)(-) complex. For instance, the reaction of allyl acetate with n-octyl alcohol in the presence of a catalytic amount of [Ir(cod)(2)](+)BF(4)(-) complex afforded allyl octyl ether in quantitative yield. Allyl carboxylates were also prepared by the exchange reaction between carboxylic acids and allyl acetate in good yields. The [Ir(cod)(2)](+)BF(4)(-) complex catalyzed the reaction of alkyl and aromatic amines with allyl acetate to lead to the corresponding allylamines in fair to good yields.

General method for the palladium-catalyzed allylation of aliphatic alcohols

A palladium catalysis-mediated approach to coupling aliphatic alcohols with allyl carbonates has been developed. The method allows for the allylation of primary, secondary, and tertiary alcohols efficiently under mild conditions. Limitations were explored as well as the asymmetric application of the chemistry. Regiochemical and olefin geometry was controlled in the coupling of unsymmetrical allylating agents. Transient allyl carbonates were observed in the coupling, which comprised the trans-carboxylation of the allyl-carbonate with the requisite alcohol.

The fluorine-containing π-allylmetal complex. The transition metal-catalyzed allylic substitution reaction of fluorinated allyl mesylates with various carbon nucleophiles

The allylic substitution reaction of [small alpha]-fluoroalkylated allyl mesylates with various carbon nucleophiles in the presence of transition metal catalyst (Pd and Mo) proceeded with high regioselectivity to give the corresponding [gamma]-fluoroalkylated products in excellent yields.

Novel approach for asymmetric synthesis of fluorinated beta-amino sulfones and allylic amines

[reaction: see text] Enantiomerically pure gamma-fluoroalkyl beta-amino sulfones are readily synthesized in three steps starting from fluorinated imidoyl chlorides and arylmethyl sulfones. A complementary two-step sequence starting from chiral fluorinated beta-amino sulfoxides has also been developed. To illustrate the application of this procedure, a new method for the synthesis of alpha-fluoroalkyl allylic amines in optically pure form involving a Julia methylenation-desulfonylation reaction is presented.