Allylation of Imines with Allylytterbium Bromide

In the presence of methyl iodide, metallic ytterbium can easily react with allylic bromide in anhydrous THF to form allylytterbium bromide, which reacts readily with imines to give the corresponding homoallylamines in satisfactory yields under mild and neutral conditions.     

Allylation of Diselenides,Aldehydes and Ketones with Ytterbium/Allyl Bromide System

In the presence of methyliodide, ytterbium can react with allyl bromide smoothly to form allylytterbium bromide, which further reacts with diselenides, aldehydes and ketones to afford allylselenides and homoallylic alcohols respectively in good yields under mild and neutral conditions.     

Tin Mediated Allylation of Aldimines with Allyl Bromide

SyntheticinterestsinhighlyfunctionalizedacyclicandcyclicamineshavecontributedtothewealthofexPerimentalmethodologydeveloPedfortheadditionofcarbanionstothecarbon-nitrogendoublebondofimines.Generally,organometallicreagentsorilltermedi-atesareusedascarbanionsandadditionofallylicorganometallicspeciestothenieconshtutesavaluablemethodforthesynthesisofhomoallylamines.'Amongthese,allyLlithium,'-magnesium,'-zinc,'-boraneandboronate,'-silaneand-stannane'havebeenusedforallylationofdriines.Ontheotherhand,…     

Allylation of Aldehydes and Ketones with Allyl Bromide and Tin Promoted by Me3SiCI and Alcohol

Allylation of aldehydes and ketones to give homoallylic alcohols can be carried out successfully with allyl bromide and metallic tin under anhydrous condition. The 64–89% yields of homoallyl alcohols are obtained by addition of chlorotrimethylsilane as a promoter in anhydrous methanol.     

Fast Ruthenium‐Catalysed Allylation of Thiols by Using Allyl Alcohols as Substrates

Green and fast : Allylation of aromatic and aliphatic thiols, by using allyl alcohols as substrates, requires only minutes at ambient temperature with a Ru catalyst (see scheme). Quantitative conversion is normal and the catalyst possesses high functional‐group tolerance.

     

Highly Diastereoselective and Enantiospecific Allylation of Ketones and Imines Using Borinic Esters: Contiguous Quaternary Stereogenic Centers

3,3‐Disubstituted allylic boronic esters are not sufficiently reactive to react with ketones and imines. However, they can be converted into the corresponding borinic esters by the sequential addition of nBuLi and TFAA. These reactive intermediates possess the perfect balance between reactivity and configurational stability. Their enhanced reactivity allows the highly selective allylation of both ketones and ketimines, and facile access to adjacent quaternary stereocenters with full stereocontrol. The versatility of the methodology is demonstrated in the construction of all possible stereoisomers of a quaternary‐quaternary motif and by the allylation of the heterocycles, dihydroisoquinoline and indole.     

Regiodivergent and Diastereoselective CuH‐Catalyzed Allylation of Imines with Terminal Allenes

A copper‐catalyzed, chemoselective hydrometalation process enables the use of simple allenes as allylmetal nucleophile surrogates in imine allylation reactions. By modulating the nitrogen‐protecting group, either highly branched‐ or linear‐selective addition can be achieved from the same allene. Both reactions exhibit excellent diastereoselectivity and broad functional‐group tolerance. Preliminary results indicate that good enantioselectivity can also be achieved in the linear‐selective reaction. Finally, a mechanistic model for the regiodivergence is proposed on the basis of density functional theory calculations.     

Oxidation of Palladium with Allyl Bromide and Iodine in Dimethylformamide

The kinetic features of palladium oxidation with allyl bromide and iodine in dimethylformamide were determined. The apparent equilibrium constants, enthalpies, and entropies of reactant adsorption on the palladium surface were calculated.     

Silver‐Catalyzed Decarboxylative Allylation of Difluoroarylacetic Acids with Allyl Sulfones in Water

A practical silver‐catalyzed decarboxylative allylation of α,α‐difluoroarylacetic acids with allyl sulfones is described, which provides a variety of β,β‐difluorinated alkenes in good yields. Notably, the reaction proceeds smoothly in water with good functional group tolerance. The practicality and synthetic value of this process was demonstrated by scaled‐up experiment and elaboration of the products via reduction or Heck reaction. Primary mechanism investigations suggest that a radical process might be involved.     

Complex Allylation by the Direct Cross‐Coupling of Imines with Unactivated Allylic Alcohols

Regioselective, stereoselective : The convergent coupling of allylic alcohols with imines to deliver stereodefined homoallylic amines is described (see scheme). The process proceeds with net allylic transposition without the intermediacy of allylic organometallic reagents. Two stereodefined centers and a geometrically defined di‐ or trisubstituted alkene are forged with high selectivity.

     

Regioselective Reactions of Pyridine-2-sulfenyl Bromide with Vinyl and Allyl Ethers

Russian Journal of General Chemistry - Annulation reactions of pyridine-2-sulfenyl bromide with vinyl and allyl ethers proceeded regioselectively, but with opposite regiochemistry. Reactions with...     

Synthesis of [3H] Dapsone

Abstract

An efficient synthesis of [³H] dapsone at high specific activity is described.     

Synthesis of Polycyclic Tertiary Carbinamines by Samarium Diiodide Mediated Cyclizations of Indolyl Sulfinyl Imines

Samarium diiodide mediated cyclizations of N‐acylated indole derivatives bearing sulfinyl imine moieties afforded polycyclic tertiary carbinamines with moderate to excellent diastereoselectivities. Lithium bromide and water turned out to be the best additives to achieve these transformations in good yields. Using enantiopure sulfinyl imines the outcome strongly depends on the reactivity of the indole moiety. Whereas with unactivated indole derivatives desulfinylation and formation of racemic products was observed, indoles bearing electron‐withdrawing substituents at C‐3 afforded the polycyclic products with intact N‐sulfinyl groups and with excellent diastereoselectivity, finally allowing the preparation of enantiopure tertiary carbinamines. The mechanisms of these processes are discussed.     

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.     

Reaction of 2-(2-Cyanoethyl)-1,1-dimethylhydrazine with Prop-2-ynyl Bromide, 1,3-Dibromopropyne,and Allyl Bromide

The reactions of 2-(2-cyanoethyl)-1,1-dimethylhydrazine with prop-2-ynyl bromide, 1,3-dibromopropyne, and allyl bromide involve alkylation by a tertiary nitrogen atom to form 2-(2-cyanoethyl)-1,1-dimethyl-1-(prop-2-ynyl)-, 1-(3-bromoprop-1-ynyl)-2-(2-cyanoethyl)-1,1-dimethyl-, and 1-allyl-2-(2-cyanoethyl)-1,1-dimethylhydrazinium bromides.