Iridium-catalyzed isomerization of primary allylic alcohols under mild reaction conditions

The isomerization of primary allylic alcohols into the corresponding aldehydes has been accomplished using an analogue of Crabtree’s iridium hydrogenation catalyst and by adequately tuning the experimental conditions. A wide range of substrates is converted quantitatively into the desired aldehyde at room temperature in expedient reaction times by using catalyst loading as low as 0.25 mol %.     

Direct allylic substitution of allyl alcohols by carbon pronucleophiles in the presence of a palladium/carboxylic acid catalyst under neat conditions

The reaction of allylic alcohols with carbon pronucleophiles in the presence of the Pd(PPh₃)₄/carboxylic acid combined catalytic system, under neat conditions (without an organic solvent or without water as the solvent) enabled the direct allylation of the pronucleophiles, giving the corresponding allylated products in high yields.     

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.     

Metal complexes in organic synthesis—V: Alkylations of pentane-2,4-dione with allylic alcohols under palladium catalysis

Pentane-2,4-dione with allylic alcohols or benzyl alcohol with palladium catalysts gives high yields of C-monoalkylated diketones, arising mainly from reaction at the terminal end of the allyic system for alkyl monosubstituted allyl alcohols. The effect of the catalyst on the alcohols has been evaluated; rearrangements and disproportionations have been observed.     

Efficient catalysis of the Suzuki-Miyaura reaction under mild conditions with cyclopalladated N,N-dimethylaminomethylferrocene

High catalytic activity of N,N-dimethylaminomethylferrocene cyclopalladated derivative was demonstrated in the the Suzuki-Miyaura cross-coupling of aryl bromides with phenylboronic acid, which allowed us to carry out the reaction under extremely mild conditions.     

Selective phenylation in mild conditions of one hydroxy group in glycols with triphenylbismuth diacetate: A new specific glycol reaction.

Refluxing for 4–5 h a dichloromethane solution of a diol in the presence of an equimolecular quantity of triphenylbismuth diacetate gave the monophenyl ether in good to excellent yield.     

A novel and selective oxidation of benzylic alcohols with polymer-supported periodic acid under mild aprotic conditions

A new polymeric oxidizing reagent was prepared by supporting periodic acid on poly（1,4-phenylene-2,5-pyridine dicarboxyamide）. This polymeric reagent was used for the selective oxidation of primary benzylic alcohols to the corresponding benzaldehydes in CH₃CN at reflux conditions.Excellent selectivity was observed between primary benzyl alcohols and secondary ones as well as non-benzylic alcohols in the oxidation reactions.Allylic alcohols were also converted to the corresponding aldehydes with good yields.     

Highly efficient oxidation of alcohols using Oxone as oxidant catalyzed by ruthenium complex under mild reaction conditions

Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone （2KHSOs-KHSO4.K2SO4） as oxidant catalyzed by ruthenium complex Quin-Ru-Quin （where Quin = 8-hydroxyquinoline）. The reaction time is very short and the preparation of complex is simple.     

Efficient nitro-aldol reaction using SmI2: a new route to nitro alcohols under very mild conditions

A novel method to obtain racemic 1-nitroalkan-2-ols by reaction of bromonitromethane with a variety of aldehydes and promoted by SmI2 is reported. On the basis of these results, the chiral version has also been performed with chiral N,N-dibenzyl amino aldehydes, affording the corresponding enantiopure 3-amino-1-nitroalkan-2-ols with good stereoselectivity.     

A simple and efficient FeCl3-catalyzed direct alkylation of active methylene compounds with benzylic and allylic alcohols under mild conditions

A highly efficient FeCl₃-catalyzed alkylation of various active methylene compounds with various benzylic or allylic alcohols under mild conditions has been developed. The reaction was carried out in the presence of a catalytic amount of anhydrous FeCl₃ (10 mol %) under reflux in methylene chloride. High to excellent yields were obtained.     

Highly efficient oxidation of alcohols using Oxone(R) as oxidant catalyzed by ruthenium complex under mild reaction conditions

Aromatic and alkyl alcohols were oxidized to the corresponding aldehydes or ketones at room temperature with high conversion and selectivity using Oxone (2KHSO5·KHSO4·K2SO4) as oxidant catalyzed by ruthenium complex Quin-Ru-Quin (where Quin = 8-hydroxyquinoline). The reaction time is very short and the preparation of complex is simple. 2008 Zi Qiang Lei. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.     

The reaction of 3-acetyl-2, 2-dimethyloxirane with phenols under conditions of acid catalysis

The reaction of 3-acetyl-2,2-dimethyloxirane with phenol and p-cresol in the presence of sulfuric acid at 70–90°C forms derivatives of 3a,9b-dihydro-4H-1,3-dioxolo[4,5-c]chromene, and also 2,2,4-trimethyl- and 2,2,4,6-tetramethylchroman-3-ones.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 11, pp. 1455–1457, November, 1973.     

Organoboranes for synthesis. 5: Stoichiometrically controlled reaction of organoboranes with oxygen under mild conditions to achieve quantitative conversion to alcohols

The reaction of organoboranes with oxygen under mild conditions can be controlled to give an essentially quantitative conversion of all three alkyl groups on boron to the corresponding alcohol. The controlled oxidation is a very clean reaction, with only minor amounts of carbonyl and hydrocarbon products formed. All organoboranes react quite rapidly in the initial stages, but vary considerably in the time required to achieve the desired uptake of oxygen. In contrast to oxidation by alkaline hydrogen peroxide, a portion of this reaction proceeds through alkyl radicals, thus resulting in some loss of stereospecificity. Oxidation of mixed organoboranes reveals that the relative rates of oxidation of alkyl groups on boron are consistent with a radical mechanism, with tertiary ⪢ secondary ⪢ primary in the rate of oxidation. The selective oxidation of one alkyl group in the presence of the other is not possible, due to small differences in relative rates of oxidation. However, thexyl and cyclohexyl groups can be selectively removed from boron in the presence of alkenyl groups. Thus, controlled oxidation of thexyldialkenylborane affords pure dialkenylborinic acid.     

Formal hydrochromination of alkynes under nickel catalysis. Regioselective reductive coupling of alkynes and aldehydes leading to allylic alcohols

Formal hydrochromation of an alkyne leading to a 1-substituted ethenylchromium reagent is accomplished by addition of the alkyne and water to a mixture of low-valent chromium(II), a catalytic amount of nickel(II), and triphenylphosphine in DMF.     

Catalytic asymmetric cyclopropanation of allylic alcohols with titanium-TADDOLate: scope of the cyclopropanation reaction.

A substoichiometric amount of titanium-TADDOLate complex was effective at catalyzing the cyclopropanation reaction of allylic alcohols in the presence 1 equiv of bis(iodomethyl)zinc. After initial optimization of the catalyst structure, excellent yields and enantiomeric ratios were obtained for 3-aryl- or 3-heteroaryl-substituted allylic alcohols (up to 97:3). Alkyl-substituted allylic alcohols gave modest yields and enantiomeric ratios (up to 87:13) but these compare favorably with those observed with other substoichiometric chiral ligands. The full synthetic scope of the reaction is presented in this paper.