Reaction Of Allylic Alcohols Research Articles

An Efficient Synthesis of Polysubstituted Dihydropyrans via Iodocyclization Reaction of Allylic Alcohols

AbstractIodomethyl‐ and sulfonyl‐containing polysubstituted dihydropyrans were synthesized conveniently in high yield by FeCl3·6H2O catalyzed iodocyclization of allylic alcohols.

Mild Two-Step Process for the Transition-Metal-Free Synthesis of Carbon−Carbon Bonds from Allylic Alcohols/Ethers and Grignard Reagents

A mild two-step process for the regioselective, transition-metal-free preparation of carbon-carbon bonds from allylic alcohols/ethers and Grignard reagents is described. This process obviates the need for the harsh deprotection conditions usually required for removal of methyl ethers. The synthesis is accomplished by photochemically promoted allylic substitution reactions of allylic alcohols and ethers with diethylphosphorothioic acid followed by sp(3)-sp(3) or sp(2)-sp(3) bond formation with various Grignard reagents under transition-metal-free conditions. Depending on the nature of the nucleophile, the regioselectivity of the carbon-carbon bond-forming event can be controlled to furnish either quaternary or tertiary carbon centers.

Concise Total Synthesis of (±)-Crinine

The concise total synthesis of (+/-)-crinine was accomplished in 24% overall yield and eleven steps starting from an easily available allylic alcohol. The key step of the current synthesis involved the NBS-promoted semipinacol rearrangement reaction of allylic alcohols. The hydroindole skeleton with the sterically congested quaternary carbon center was established concisely by utilizing this semipinacol rearrangement followed by a combination of intramolecular aldol and aza-Michael reactions.

Gas phase reaction of allyl alcohol (2-propen-1-ol) with OH radicals and ozone

The gas phase reactions of allyl alcohol with OH radicals and ozone have been investigated using different experimental systems. The rate coefficient for the OH reaction is reported in the temperature range 231-373 K, k(OH) = (5.7 +/- 0.2) x 10(-12) exp[(650 +/- 52)/T] cm3 molecule(-1) s(-1). This reaction is found to be pressure independent between 33 and 760 Torr. Rate coefficient (k(O3)) and gas phase products of the ozone reaction with allyl alcohol are reported at atmospheric pressure and 298 K. The obtained k(O3) = (1.8 +/- 0.2) x 10(-17) cm3 molecule(-1) s(-1) is in good agreement with the single measurement reported in the literature. The reaction of 03 with allyl alcohol is found to lead to the formation of formaldehyde and glycolaldehyde as the main products. Other products such as CH3OH, CO and CO2 have also been observed in low yield. Aerosol formation has been detected in the ozonolysis of allyl alcohol and its size distribution investigated.

ChemInform Abstract: Palladium(0)‐Catalyzed Direct Cross‐Coupling Reaction of Allylic Alcohols with Aryl‐ and Alkenylboronic Acids.

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Tandem Aziridination/Rearrangement Reaction of Allylic Alcohols: An Efficient Approach to 2-Quaternary Mannich Bases

A novel tandem aziridination/rearrangement reaction of allylic alcohols has been discovered, in which the significant accelerating effect of silica gel has been identified. On the basis of this methodology, an efficient and highly stereoselective approach to various 2-quaternary Mannich bases has been put in place, readily providing an alternative route to the conventional vicinal amino-functionalization of alkenes.

Asymmetric Simmons–Smith Reaction of Allylic Alcohols with Al Lewis Acid/N Lewis Base Bifunctional Al(Salalen) Catalyst

Asymmetric Simmons–Smith Reaction of Allylic Alcohols with Al Lewis Acid/N Lewis Base Bifunctional Al(Salalen) Catalyst

Asymmetric Simmons–Smith Reaction of Allylic Alcohols with Al Lewis Acid/N Lewis Base Bifunctional Al(Salalen) Catalyst

Asymmetric Simmons–Smith Reaction of Allylic Alcohols with Al Lewis Acid/N Lewis Base Bifunctional Al(Salalen) Catalyst

Palladium(0)-catalyzed direct cross-coupling reaction of allylic alcohols with aryl- and alkenylboronic acids

Allylic alcohols can be used directly for the palladium(0)-catalyzed allylation of aryl- and alkenylboronic acids with a wide variety of functional groups. A triphenylphosphine-ligated palladium catalyst turns out to be most effective for the cross-coupling reaction and its low loading (less than 1 mol%) leads to formation of the coupling product in high yield. The Lewis acidity of the organoboron reagents and poor leaving ability (high basicity) of the hydroxyl group are essential for the cross-coupling reaction. The reaction process is atom-economical and environmentally benign, because it needs neither preparation of allyl halides and esters nor addition of stoichiometric amounts of a base. Furthermore, allylic alcohols containing another unsaturated carbon-carbon bond undergo arylative cyclization reactions leading to cyclopentane formation.

Arylation of Allyl Alcohols in Organic and Aqueous Media Catalyzed by Oxime‐Derived Palladacycles: Synthesis of β‐Arylated Carbonyl Compounds

AbstractA 4‐hydroxyacetophenone oxime‐derived palladacycle catalyzes the Mizoroki–Heck reaction of allyl alcohols with aryl iodides, bromides, and chlorides in aqueous and organic solvents. The reaction takes place in the presence of dicyclohexylmethylamine or cesium carbonate as bases, the addition of tetrabutylammonium bromide (TBAB) as additive for aryl bromides and chlorides being necessary. Under these reaction conditions, β‐arylated aldehydes and ketones are mainly obtained using a rather low loading of palladium (0.1–1 mol %). Similar catalytic activity is shown by a Kaiser oxime resin‐derived palladacycle, which allows one to perform recycling and reusing experiments with low Pd leaching. The high regio‐ and chemoselectivity observed supported that these palladacycles, working as a source of Pd(0) species, operates mainly through a neutral mechanism. This methodology has been applied to the synthesis of important β‐arylated carbonyl compounds, such as 4‐phenylbutan‐2‐one, 4‐(4‐hydroxyphenyl)butan‐2‐one, dihydrochalcones, the anti‐inflamatory nabumetone, and the fragance β‐lilial®. γ‐Arylation is observed in the reactions of allyl alcohol and but‐3‐en‐2‐ol with 2‐iodoaniline giving mainly the corresponding quinolines. The same tendency is observed in the case of 1,1‐dimethylallyl alcohol affording either γ‐arylated alcohols or (E)‐1‐arylisoprenes.

Cover Picture: Procedures for and Possible Mechanisms of Pd‐Catalyzed Allylations of Primary and Secondary Amines with Allylic Alcohols (Eur. J. Org. Chem. 19/2007)

AbstractThe cover picture shows the palladium‐catalyzed intermolecular reaction of allylic alcohols with amines. The advantages of this process are the easily available substrates, the high atom economy, and the formation of only water as the by‐product. Details of this reaction are presented in the Microreview by J. Muzart on p. 3077 f. The slides that form the frame of the scheme, with the French flag in the background, show the Champagne area and highlight the well‐known sparkling product of the region and the Reims cathedral. Emilie Thiery and Dr. Jean Le Bras are acknowledged for preparing the artwork for the cover picture.

Reactions of Allyl Alcohols of the Pinane Series and of Their Epoxides in the Presence of Montmorillonite Clay

AbstractThe reactivity of allyl alcohols of the pinane series and of their epoxides in the presence of montmorillonite clay in intra‐ and intermolecular reactions was studied. Mutual transformations of (+)‐trans‐pinocarveol ((+)‐2) and (−)‐myrtenol ((−)‐3a) were major reactions of these compounds on askanite–bentonite clay (Schemes 1 and 2). However, the two reactions gave different isomerization products, indicating that the reactivity of the starting alcohol (+)‐2 or (−)‐3a was different from that of the same compound (+)‐2 or (−)‐3 formed in the course of the reactions. (−)‐cis‐ and (+)‐trans‐Verbenol ((−)‐16 and (+)‐12, resp.), as well as (−)‐cis‐verbenol epoxide ((−)‐20) reacted with both aliphatic and aromatic aldehydes on askanite–bentonite clay giving various heterocyclic compounds (Schemes 4, 5 and 7); the reaction path depended on the structure of both the terpenoid and the aldehyde.

Stereoselective synthesis of functionalized 1,3 diols through the tandem isomerization–aldolization reaction mediated by nickel catalysts

A new approach to functionalized 1,3 diols, such as 15, is described using as the key step the tandem isomerization–aldolization reaction of allylic alcohols 1. The chiral imidazolidine group is shown to play a key role for the stereocontrol during aldolization and reduction steps.

A Comparison of Intrazeolite and Solution Singlet Oxygen Ene Reactions of Allylic Alcohols

The singlet oxygen ene reactions of four allylic alcohols and for comparison an allylic ether have been examined both in solution and in zeolite Y. Brønsted acid sites in the zeolite were shown to induce decomposition of several of the allylic alcohols. Treatment of the zeolites with pyridine removed these acid sites and allowed intrazeolite reactions of the allylic alcohols without interference from decomposition. Control reactions with an allylic alcohol that is inert to decomposition provided evidence that the presence of pyridine in the zeolite labyrinth does not influence the product composition.

Palladium-catalyzed substitution reactions of 4-allylimidazole derivatives

In the context of synthetic studies toward the oroidin family of pyrrole–imidazole alkaloids, we required an efficient method for conducting substitution reactions of allylic alcohols derived from urocanic acid. While in some cases this could be accomplished quite readily by classical nucleophilic substitution, it was complicated by allylic transposition in others. Application of Pd-catalyzed π–allyl chemistry provided a convenient solution, giving substitution without allylic transposition. Herein we describe the scope of this reaction in imidazole-containing substrates, and the elaboration of one adduct into a homologated histidine derivative, and into a cyclic homohistidine derivative.

From Allylic Alcohols to Aldols through a New Nickel‐Mediated Tandem Reaction: Synthetic and Mechanistic Studies

Nickel hydride type complexes have been successfully developed as catalysts for the tandem isomerization-aldolization reaction of allylic alcohols with aldehydes. Optimization of the reaction conditions has shown that a cocatalyst, such as MgBr2, has a very positive effect on the kinetics of the reaction and in the yields of aldols. Under such optimized conditions {[NiHCl(dppe)] + MgBr(2) at 3-5 mol %)}, this reaction affords the aldols in good to excellent yields. It is a full-atom-economy-type reaction that occurs under mild conditions. Furthermore, it has a broad scope for the allylic alcohols and it is compatible with a wide range of aldehydes, including very bulky derivatives. The reaction is completely regioselective, but it exhibits a low stereoselectivity, except for allylic alcohols with a bulky substituent at the carbinol center. The use of chiral nonracemic catalysts was not successful, affording only racemic compounds. However, it was possible to use asymmetric synthesis for the preparation of optically active aldols. Various mechanistic studies have been performed using, for instance, a deuterated alcohol or a deuterated catalyst. They gave strong support to a mechanism involving first a transition-metal-mediated isomerization of the allylic alcohol into the free enol, followed by the addition of the latter intermediate onto the aldehyde in an "hydroxyl-carbonyl-ene" type reaction. These results confirm that allylic alcohols can be considered as new and useful partners in the development of the aldol reaction.

Heterogeneous Hydrogenation Catalyses over Recyclable Pd(0) Nanoparticle Catalysts Stabilized by PAMAM-SBA-15 Organic−Inorganic Hybrid Composites

Pd(0) nanoparticle catalysts stabilized by Gn-PAMAM-SBA-15 (n = 1-4) organic-inorganic hybrid composites were successfully prepared. Heterogeneous hydrogenation reaction of allyl alcohol over the Pd(0)-Gn-PAMAM-SBA-15 catalysts showed their high activities with TOFs of 2185, 2266, 711, and 739 and selectivities of 79.0, 82.0, 93.4, and 91.4%, respectively. The activity over the Pd(0)-G4-PAMAM-SBA-15 catalyst was 1.5 times that over the fourth generation PAMAM encapsulated Pd(0) homogeneous catalyst. These catalysts can be easily recovered, reused multiple times, and preserved for one month in the air, maintaining high catalytic efficiencies.

Highly efficient Barbier allylation from allyl alcohol using iridium(I)/tin(II): Unusual and indirect roles of allyl alcohol and tin

A reagent combination of SnCl 2 and catalytic [Ir(COD)Cl] 2 (1 mol%) in THF–H 2O promotes the reaction of allyl alcohol and aldehyde leading to homoallyl alcohols in good to excellent yields. Control studies suggest the plausible participation of π-allyl-iridium intermediate(s) from which direct allyl transfer takes place to aldehyde.

Cross–Coupling Reactions of Allylic Alcohols in Water

AbstractPalladium–catalyzed cross–coupling reactions of allylic alcohols and arylboronic acids in water are described. The reactions proceeded smoothly in water at reflux using catalytic amounts of [Pd(allyl)Cl]2 and PPh3. Addition of a catalytic amount of a base allowed the reaction to proceed even at lower temperatures.

A Highly Effective (Triphenyl phosphite)palladium Catalyst for a Cross—Coupling Reaction of Allylic Alcohols with Organoboronic Acids.

AbstractFor Abstract see ChemInform Abstract in Full Text.