Bond Of Allylic Alcohol Research Articles

Loop-Grafted Old Yellow Enzymes in the Bienzymatic Cascade Reduction of Allylic Alcohols.

The enzymatic reduction of C=C bonds in allylic alcohols with Old Yellow Enzymes represents a challenging task, due to insufficient activation through the hydroxy group. In our work, we coupled an alcohol dehydrogenase with three wild-type ene reductases-namely nicotinamide-dependent cyclohex-2-en-1-one reductase (NCR) from Zymomonas mobilis, OYE1 from Saccharomyces pastorianus and morphinone reductase (MR) from Pseudomonas putida M10-and four rationally designed β/α loop variants of NCR in the bienzymatic cascade hydrogenation of allylic alcohols. Remarkably, the wild type of NCR was not able to catalyse the cascade reaction whereas MR and OYE1 demonstrated high to excellent activities. Through the rational loop grafting of two intrinsic β/α surface loop regions near the entrance of the active site of NCR with the corresponding loops from OYE1 or MR we successfully transferred the cascade reduction activity from one family member to another. Further we observed that loop grafting revealed certain influences on the interaction with the nicotinamide cofactor.

ChemInform Abstract: Further Study on the Regioselectivity of (Dimethylvinylidene)carbene upon the Cycloaddition to the α,β-Unsaturated Double Bond of an Allylic Alcohol and the Normal Olefinic Group.

Abstract Further study on the regioselective addition of vinylidenecarbene 1 to the α,β-unsaturated double bond of allylic alcohol and the normal olefinic group is described. This selectivity was found to be influenced by both of the allylic hydroxy group and the degree of alkyl substitution of the double bonds.

Ruthenium-catalyzed redox isomerization/transfer hydrogenation in organic and aqueous media: A one-pot tandem process for the reduction of allylic alcohols

The hexamethylbenzene-ruthenium(II) dimer [{RuCl(μ-Cl)(η6-C6Me6)}2] 1 and the mononuclear bis(allyl)-ruthenium(IV) complex [RuCl2(η3:η2:η3-C12H18)] 2, associated with base and a hydrogen donor, were found to be active catalysts for the selective reduction of the CC bond of allylic alcohols both in organic and aqueous media. The process, which proceeds in a one-pot manner, involves a sequence of two independent reactions: (i) the initial redox-isomerization of the allylic alcohol, and (ii) subsequent transfer hydrogenation of the resulting carbonyl compound. The highly efficient transformation reported herein represents, not only an illustrative example of auto-tandem catalysis, but also an appealing alternative to the classical transition-metal catalyzed CC hydrogenations of allylic alcohols. The process has been successfully applied to aromatic as well as aliphatic substrates affording the corresponding saturated alcohols in 45–100% yields after 1.5–24 h. The best performances were reached using (i) 1–5 mol% of 1 or 2, 2–10 mol% of Cs2CO3, and propan-2-ol or (ii) 1–5 mol% of 1 or 2, 10–15 equivalents of NaO2CH, and water. The catalytic efficiency is strongly related to the structure of the allylic alcohol employed. Thus, in propan-2-ol, the reaction rate essentially depends on the steric requirement around the CC bond, therefore decreasing with the increasing number of substituents. On other hand, in water the transformation is favoured for primary allylic alcohols vs. secondary ones.

Direct palladium/carboxylic acid-catalyzed C-allylation of cyclic 1,3-diones with allylic alcohols in water

The direct activation of C–O bonds in allylic alcohols in water as a suspension medium by palladium complexes has been accelerated by carrying out the reactions in the presence of a carboxylic acid. The palladium-catalyzed allylation of cyclic 1,3-diones using allylic alcohols directly gave the corresponding C-allylated products in good yields.

Direct palladium/carboxylic acid-catalyzed allylation of anilines with allylic alcohols in water

The direct activation of C–O bonds in allylic alcohols in water as a suspension medium by palladium complexes has been accelerated by carrying out the reactions in the presence of a carboxylic acid. The palladium-catalyzed allylation of anilines using allylic alcohols directly gave allylic anilines in good yields.

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.

Direct Palladium(0)‐Catalyzed Amination of Allylic Alcohols with Aminonaphthalenes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Direct palladium(0)-catalyzed amination of allylic alcohols with aminonaphthalenes

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 reagents. The palladium-catalyzed amination of allylic alcohols using aminonaphthalenes gave N-allylic naphthylamines in good yields. The monoallylation products are formed in the main.

Direct Platinum-Catalyzed Allylation of Anilines Using Allylic Alcohols

A simple and efficient route for the preparation of N-allylanilines by the direct use of allylic alcohols has been developed. The direct activation of C−O bonds in allylic alcohols by platinum complexes has been accelerated by carrying out the reactions in the presence of titanium reagents. The platinum-catalyzed allylation of anilines using allylic alcohols directly gave allylic anilines in good yields. Anilines bearing an electron-withdrawing group gave lower chemical yields.

Regio- and Stereoselectivity in Palladium(0)-Catalyzed Allylation of 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) isopropoxide and 4 Å molecular sieves. The palladium(0)-catalyzed allylation of anilines using allylic alcohols directly gave regio- and stereoisomeric allylic anilines in good yields. The regioselectivity of the process was temperature dependent. Under kinetic control, the less highly substituted alkene was obtained, while under thermodynamic control the more highly substituted alkene was increased. Anilines bearing an electron-withdrawing group gave lower chemical yields. The phosphine ligand effect was very important on the regioselectivity: decreasing the size of the diphosphines or decreasing the electron-withdrawing ability of the monophosphines gave predominantly the less highly substituted alkenes.

ChemInform Abstract: Activation of C‐O and C‐N Bonds in Allylic Alcohols and Amines by Palladium Complexes Promoted by CO2. Synthetic Applications to Allylation of Nucleophiles, Carbonylation, and Allylamine Disproportionation.

AbstractChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.

Activation of C–O and C–N Bonds in Allylic Alcohols and Amines by Palladium Complexes Promoted by CO2. Synthetic Applications to Allylation of Nucleophiles, Carbonylation, and Allylamine Disproportionation

Abstract The direct activation of the C–O bonds in allylic alcohols catalyzed by palladium complexes has been accelerated by carrying out the reactions under CO2. On reaction with diethylamine, allyl alcohol can be converted into N,N-diethylallylamine in the presence of palladium complexes at room temperature under normal pressure of carbon dioxide. Allylation of various carbon nucleophiles such as β-keto esters and β-diketones can be achieved by using allylic alcohols directly in the presence of palladium complexes and CO2. Direct carbonylation of allylic alcohols into unsaturated carboxylic acids can be catalyzed by palladium complexes under the pressure of CO and CO2. Disproportionation of diallylamine into triallylamine and allylamine is also catalyzed by palladium complexes in the presence of CO2. On the basis of studies on the behavior of η3-allylpalladium hydrogencarbonate complexes with the nucleophiles, mechanisms are proposed to account for the palladium-catalyzed allylation processes influenced by CO2.

Cob (I)alamin als Katalysator 4. Mitteilung. Reduktion von α,β‐ungesättigten Nitrilen

AbstractCob(I)alamin as Catalyst. 4. Communication. Reduction of α,β‐Unsaturated NitrilesUsing catalytic amounts of cob (I)alamin and an excess of metallic zinc as source of electrons 1‐naphthonitril (5) has been reduced to (1‐naphthyl)methylamin (6) and in small amounts to (1‐naphthyl)methanol (7) and (1,2,3,4‐tetrahydro‐1‐naphthyl)methanol (8) (5 ½ h, CH3COOH/H2O; s. Scheme 3). Starting from cyclododecylideneacetonitrile (15) similar conditions (68 h, CH3COOH/H2O) produced the amines 16–19 as well as the nitrogen free saturated aldehyde 20, the corresponding allylic alcohol 21 and the saturated derivative 22 (s. Scheme 6). It is deduced that the first attack of cob (I)alamin on an α,β‐unsaturated nitrile might occur on both the nitrile dipole as well as on the carbon atom in β‐position. Cob (I)alamin in aqueous acetic acid saturates the isolated double bonds in allylic alcohols and amines. In a slow reaction the two different aromatic rings of (1‐naphthyl)methanol (7) have been reduced giving the corresponding tetrahydronaphthalene derivatives 8 and 12, and in one case the production of the octahydroderivative 14 has been observed in a low yield (s. Scheme 5).