- Formyloxyacetoxyphenylmethane and 1,1-diacylals as versatile O-formylating and O-acylating reagents for alcohols
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Formyloxyacetoxyphenylmethane, symmetric 1,1-diacylals and mixed 1-pivaloxy-1-acyloxy-1-phenylmethanes have been used as moisture stable O-formylating and O-acylating reagents for primary and secondary alcohols, allylic alcohols and phenols under solvent/catalyst free conditions to afford their corresponding esters in good yield.
- Chapman, Robert S.L.,Francis, Molly,Lawrence, Ruth,Tibbetts, Joshua D.,Bull, Steven D.
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p. 6442 - 6452
(2018/10/02)
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- Efficient O-Acylation of Alcohols and Phenol Using Cp2TiCl as a Reaction Promoter
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A method has been developed for the conversion of primary, secondary, and tertiary alcohols, and phenol, into the corresponding esters at room temperature. The method uses a titanium(III) species generated from a substoichiometric amount of titanocene dichloride together with manganese(0) as a reductant, as well as methylene diiodide. It involves a transesterification from an ethyl ester, or a reaction with an acyl chloride. A radical mechanism is proposed for these transformations.
- Durán-Pe?a, María Jesús,Botubol-Ares, José Manuel,Hanson, James R.,Hernández-Galán, Rosario,Collado, Isidro G.
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supporting information
p. 3584 - 3591
(2016/07/28)
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- Titanium carbenoid-mediated cyclopropanation of allylic alcohols: Selectivity and mechanism
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A new method for the chemo- and stereoselective conversion of allylic alcohols into the corresponding cyclopropane derivatives has been developed. The cyclopropanation reaction was carried out with an unprecedented titanium carbenoid generated in situ from Nugent's reagent, manganese and methylene diiodide. The reaction involving the participation of an allylic hydroxyl group, proceeded with conservation of the alkene geometry and in a high diastereomeric excess. The scope, limitations and mechanism of this metal-catalysed reaction are discussed. This journal is
- Durán-Pe?a,Botubol-Ares,Hanson,Hernández-Galán,Collado
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p. 6325 - 6332
(2015/06/08)
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- Enantiomeric differentiation of oxygenated p-menthane derivatives by 13C NMR using Yb(hfc)3
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The 13C NMR behaviour of 21 p-menthanic terpene bearing an oxygenated function (alcohol, ketone, acetate) was examined in the presence of a chiral lanthanide shift reagent (Yb(hfc)3). For each monocyclic compound, we measured the lanthanide-induced shift (LIS) on the signals of the carbons and the splitting of signals allowing the enantiomeric differentiation. Some general features were found about their LIS behaviour: experimental data establishing distinct patterns for carvomenthone-like compounds and menthone-like compounds. The enantiomeric splitting was observed for the majority of signals in the spectrum of each compound. In the case of alcohols and acetates, the influence of the relative stereochemistry (cis vs trans) of isopropyl(ene) and the binding function was discussed. Copyright
- Lanfranchi, Don Antoine,Blanc, Marie-Cecile,Vellutini, Muriel,Bradesi, Pascale,Casanova, Joseph,Tomi, Felix
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experimental part
p. 1188 - 1194
(2009/05/26)
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- The claisen rearrangement in synthesis: Acceleration of the johnson orthoester protocol en route to bicyclic lactones
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Catalysis of the Claisen orthoester rearrangement of triethyl orthoacetate and a number of 2-cycloalken-1-ols has been achieved using acidic catalysis and brief microwave thermolysis in DMF. Unlike conventional methods of thermolysis, very high yields of rearranged products are typically obtained in less than ten minutes, and the Claisen products themselves require no further purification. The synthetic utility of the products so obtained is demonstrated in a general synthesis of functionalized bicyclic lactones.
- Jones, Graham B.,Huber, Robert S.,Chau, Sotheary
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p. 369 - 380
(2007/10/02)
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- Microbial Allyl Rearrangement and Resolution of Acetates of Unsaturated Cyclic Terpene Alcohols by Pseudomonas sp. NOF-5 Strain
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Microbial hydrolysis of the acetates of unsaturated cyclic terpene alcohols by Pseudomonas sp.NOF-5 isolated from soil was investigated. (+/-)-trans-Carveyl acetate ((+/-)-trans-3) was enantioselectively hydrolyzed with NOF-5 strain to give (-)-trans-carveol ((-)-trans-2 of 86.6percent optical purity).However, the hydrolysis of (+/-)-cis-3 was less enantioselective, while (+/-)-piperitylacetate ((+/-)-6, a cis and trans mixture) was hydrolyzed to give the (-)-trans- and (-)-cis-piperitols ((-)-trans-5 and (-)-cis-5) in a poor optical yield.In this case, other tert-alcohols, (+)-trans- and (-)-cis-2-p-menthen-1-ols ((+/-)-trans-7 and (-)-cis-7, were also produced.Furthermore, microbial and enzymic allyl rearrangements of (+)-trans-6 and (-)-trans-verbenylacetate ((-)-trans-11) were studied.Biological treatment of (+)-trans-6 and (-)-trans-11 with NOF-5 or its esterase gave (+)-trans- and (-)-cis-7 and (+)-cis-3-pinen-2-ol ((+)-cis-12), respectively.
- Inagaki, Takashi,Ueda, Hiroo
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p. 2635 - 2640
(2007/10/02)
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- Reactions of d-Limonene with t-Butyl Hypochlorite
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Investigation of the title reaction under different conditions of temperature, solvents and catalysis has led to its optimisation with respect to the yield of (-)-trans-carvyl chloride (2).Other products formed in the reaction have been identified as 1,2-dichloro-p-menth-8-ene (5), 10-chloro-p-mentha-1,8-diene (6), 2-chloro-p-mentha-1(7)8-diene (10) and 6,10-dichloro-p-mentha-1,8-diene (11).The reaction proceeds almost entirely by electrophilic halogenation with no evidence of competition from a radical mechanism.
- Ravindranath, B.,Srinivas, P.
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p. 163 - 165
(2007/10/02)
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- NUCLEOPHILIC SUBSTITUTION OF ALKYL HALIDES BY ZINC SALTS-3 PREPARATION OF TERTARY ALKYL ESTERS AND ETHERS UNDER NON-SOLVOLYTIC CONDITIONS
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Zinc salts of carboxylic acids, phenols and alcohols are found to react with tertiary alkyl halides in nonpolar solvents and in presence of a base yielding the corresponding esters and ethers in moderate to good yields.
- Ravindranath, B.,Srinivas, P.
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p. 1623 - 1628
(2007/10/02)
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- TO WHAT EXTENT IS A ?-ALLYLIC INTERMEDIATE INVOLVED IN SOME PALLADIUM-CATALYZED ALKYLATIONS ?
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Comparison of polarimetric data in the asymmetric palladium-catalyzed addition of sodium dimethyl malonate on optically active and racemic 2-cyclohexenyl and carveyl acetates suggests that the reaction does not got- at least totally -through a symmetric ?-allylic cationic intermediate.
- Fiaud, J. C.,Malleron, J. L.
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p. 1399 - 1402
(2007/10/02)
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- Enzymic Resolution of (+/-)-Unsaturated Cyclic Terpene Alcohols via Asymmetric Hydrolysis of Corresponding Acetates by Microorganisms
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Asymmetric hydrolysis of the acetates of (+/-)-cis and trans-carveols by microorganisms or their esterase produced chiral cis and trans-carveols and the acetates of their enantiomers.The enantioselectivity of the microbial hydrolysis and the optical purities of the products varied with the species of microorganisms.This method was also applied in separation of diastereomeric mixtures of (-)-carveols and (-)-7-epi-α-cyperols.
- Oritani, Takayuki,Yamashita, Kyohei
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p. 2637 - 2642
(2007/10/02)
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