Nucleophilic Allylation Research Articles

Transition metal-free generation of N-unsubstituted imines from benzyl azides: synthesis of N-unsubstituted homoallylic amines.

An efficient transition metal-free approach for the generation of N-unsubstituted imines from azides followed by trapping with allyl nucleophile to provide N-unsubstituted homoallylic amines has been described. Although catalytic KO(t)Bu in DMSO is sufficient to allow imine generation, stoichiometric KO(t)Bu is essential in THF. Further, an enantio- and diastereoselective synthesis of homoallylic amines from benzyl azide has also been exemplified.

Gold-Catalyzed Benzylic Azidation of Phthalans and Isochromans and Subsequent FeCl3-Catalyzed Nucleophilic Substitutions.

The benzylic positions of the phthalan and isochroman derivatives (1) as benzene-fused cyclic ethers effectively underwent gold-catalyzed direct azidation using trimethylsilylazide (TMSN3) to give the corresponding 1-azidated products (2) possessing the N,O-acetal partial structure. The azido group of the N,O-acetal behaved as a leaving group in the presence of catalytic iron(III) chloride, and 1-aryl or allyl phthalan and isochroman derivatives were obtained by nucleophilic arylation or allylation, respectively. Meanwhile, a double nucleophilic substitution toward the 1-azidated products (2) occurred at the 1-position using indole derivatives as a nucleophile accompanied by elimination of the azido group and subsequent ring opening of the cyclic ether nucleus produced the bisindolylarylmethane derivatives.

Palladium-Catalyzed Nucleophilic Allylation of Aldehydes or Aldimines

Palladium-Catalyzed Nucleophilic Allylation of Aldehydes or Aldimines

ChemInform Abstract: Catalytic, Nucleophilic Allylation of Aldehydes with 2‐Substituted Allylic Acetates: Carbon—Carbon Bond Formation Driven by the Water—Gas Shift Reaction.

AbstractThe ruthenium—catalyzed allylation of aldehydes (aromatic, α,β‐unsaturated, and aliphatic aldehydes) with allylic acetates is expanded to incorporate substituents at the 2‐position of the allylic component.

The isomerization of allylrhodium intermediates in the rhodium-catalyzed nucleophilic allylation of cyclic imines.

Allylrhodium species generated from potassium allyltrifluoroborates can undergo isomerization by 1,4-rhodium(I) migration to give more complex isomers, which then react with cyclic imines to provide products with up to three new stereochemical elements. High enantioselectivities are obtained using chiral diene–rhodium complexes.

The Isomerization of Allylrhodium Intermediates in the Rhodium‐Catalyzed Nucleophilic Allylation of Cyclic Imines

AbstractAllylrhodium species generated from potassium allyltrifluoroborates can undergo isomerization by 1,4‐rhodium(I) migration to give more complex isomers, which then react with cyclic imines to provide products with up to three new stereochemical elements. High enantioselectivities are obtained using chiral diene–rhodium complexes.

Catalyst-directed diastereo- and site-selectivity in successive nucleophilic and electrophilic allylations of chiral 1,3-diols: protecting-group-free synthesis of substituted pyrans.

The iridium-catalyzed, protecting group-free synthesis of 4-hydroxy-2,6-cis- or trans-pyrans through successive nucleophilic and electrophilic allylations of chiral 1,3-diols occurs with complete levels of catalyst-directed diastereoselectivity in the absence of protecting groups, premetallated reagents, or discrete alcohol-to-aldehyde redox reactions.

Synthesis of Lactones and Lactams from Vinylcyclopropane by Palladium- Catalyzed Nucleophilic Allylation

A palladium-catalyzed nucleophilic allylation of aldehydes with vinylcyclopropane in the presence of diethylzinc proceeded to provide homoallyl alcohols with anti stereoselectivity. Aldimines prepared from aldehyde and primary amines in situ underwent a similar nucleophilic allylation to give homoallylamines with syn stereoselectivity. The resulting homoallyl alcohols and homoallylamines could be converted by treatment with a tetranuclear zinc cluster into γ-vinyl-δ-valerolactones and γ-vinyl-δ-valerolactams, respectively.

Catalytic, nucleophilic allylation of aldehydes with 2-substituted allylic acetates: carbon-carbon bond formation driven by the water-gas shift reaction.

The ruthenium-catalyzed allylation of aldehydes with allylic acetates has been expanded to incorporate substituents at the 2-position of the allylic components. Allylic acetates bearing a variety of substituents (CO2-t-Bu, COMe, Ph, CH(OEt)2, and Me) undergo high-yielding additions with aromatic, α,β-unsaturated, and aliphatic aldehydes. The conditions of the reaction were found to be mild (75 °C, 24-48 h) and only required the use of 2-3 mol % of the triruthenium dodecacarbonyl catalyst under 40-80 psi of CO. The stoichiometries of water and allylic acetate employed were found to be critical to reaction efficiency.

Short‐Step Anodic Access to Emissive RNA Homonucleosides (Eur. J. Org. Chem. 7/2014)

The cover picture shows a schematic impression of our synthetic approach toward new emissive nucleoside analogues. Our methodology employs an anodic oxidation of methoxyphenols (right) in lithium perchlorate/nitromethane electrolyte solution, generating reactive phenoxonium ions, which were then trapped by nucleophilic allyl ribose (left) to construct emissive base analogues in one step from non-emissive starting materials. The straight one-way road represents a short-step synthesis, and allyl ribose should “yield” the right-of-way to methoxyphenols to “yield” the desired products. Details are discussed in the Short Communication by K. Chiba et al. on p. 1371 ff.

Efficient Allylation of Nucleophiles Catalyzed by a Bifunctional Heterogeneous Palladium Complex‐Tertiary Amine System

AbstractWe demonstrate the synergistic catalysis of a silica‐supported diaminopalladium complex and a tertiary amine (SiO2/diamine/Pd/NEt2) as well as synthetic scope of the Tsuji–Trost reaction of 1,3‐dicarbonyls, phenols, and carboxylic acids with allyl carbonate and acetates. The synergistic catalysis of SiO2/diamine/Pd/NEt2 exhibited wide applicability and high activity for the Tsuji–Trost reaction. For example, the reaction of ethyl 3‐oxobutanate with allyl methyl carbonate afforded the allylated product in >99% yield at 70 °C for 5 h. The yield of allylated products was 26% for SiO2/diamine/Pd, without immobilization of the tertiary amine group. In the reaction of 1.0 mmol of ethyl 3‐oxobutanate using 0.60 μmol of Pd in SiO2/diamine/Pd/NEt2, the turnover number (TON) of Pd reached up to 1070 within 24 h. Phenols with electron‐withdrawing groups, such as nitro and chloro groups, on the para position resulted in high product yields. The SiO2/diamine/Pd/NEt2 catalyst was reusable at least 4 times without appreciable loss of its activity and selectivity in the reaction of p‐chlorophenol.

ChemInform Abstract: Enantioselective Rhodium‐Catalyzed Nucleophilic Allylation of Cyclic Imines with Allylboron Reagents.

AbstractThe title reaction represents the first rhodium‐catalyzed enantioselective nucleophilic allylation of π‐electrophiles with allylboron compounds.

Rhodium-Catalyzed Enantioselective Nucleophilic Allylation of Imines

Rhodium-Catalyzed Enantioselective Nucleophilic Allylation of Imines

ChemInform Abstract: Transition Metal Catalyzed Nucleophilic Allylic Substitution: Activation of Allylic Alcohols via π‐Allylic Species

AbstractReview: about 100 refs.

Enantioselective Rhodium‐Catalyzed Nucleophilic Allylation of Cyclic Imines with Allylboron Reagents

Chirale Allylrhodium-Nucleophile: Die hoch diastereo- und enantioselektive Titelreaktion einer Reihe cyclischer Imine mit mehreren Kaliumallyltrifluoroboraten (siehe Schema) verläuft höchstwahrscheinlich über ein Allylrhodium(I)-Intermediat und ist die erste rhodiumkatalysierte enantioselektive nucleophile Allylierung von π-Elektrophilen mit Allylborverbindungen.

Enantioselective Rhodium‐Catalyzed Nucleophilic Allylation of Cyclic Imines with Allylboron Reagents

The title reaction represents the first rhodium-catalyzed enantioselective nucleophilic allylation of π-electrophiles with allylboron compounds.

Transition metal catalyzed nucleophilic allylic substitution: activation of allylic alcohols via π-allylic species

Modern organic synthesis now requires efficient atom economical synthetic methods operating under greener pathways to achieve C-C and C-heteroatom bond formation. Direct activation of allylic alcohols in the presence of transition metal catalysts leading to electrophilic π-allyl metal intermediates represents such a promising target in the field of nucleophilic allylation reactions. During the last decade, this topic of recognized importance has become an emerging area, and selected transition metals, sometimes associated with alcohol activators, have brought elegant solutions for performing allylic substitution directly from alcohols in a regio, stereo and enantioselective manner.

First example of a heterobimetallic ‘Pd–Sn’ catalyst for direct activation of alcohol: efficient allylation, benzylation and propargylation of arenes, heteroarenes, active methylenes and allyl-Si nucleophiles

Arenes, heteroarenes, 1,3-dicarbonyls and organosilicon nucleophiles undergo highly efficient alkylation with allylic, propargylic and benzylic alcohols in the presence of a new 'Pd-Sn' bimetallic catalyst in nitromethane; water being the sole byproduct. The plausible mechanism of alkylation and the intermediacy of ether has been enumerated.

A simple diamine as ligand in iron-catalyzed regioselective allylic alkylation

A simple and efficient diamine was found to be an efficient ligand for the iron-catalyzed regioselective allylic alkylation between various allyl carbonates and nucleophiles, affording excellent yields and good regioselectivity (up to 94% and >20 : 1).

ChemInform Abstract: Catalytic Asymmetric Conjugate Allylation of Coumarins.

AbstractA dual catalytic strategy is applied: the Yb complex activates the coumarin and the Cu cocatalyst generates an active allyl nucleophile by transmetalation.