20127-07-5Relevant articles and documents
Reaction of Di(bromomagnesio)alkanes with Cyclic Dicarboxylic Acid Anhydrides
Canonne, Persephone,Belanger, Denis
, p. 125 - 126 (1980)
The reaction of the di(bromomagnesio)alkanes BrMg4MgBr and BrMg5MgBr with cyclic anhydrides produces spirolactones in one step in good yield.
Synthesis and Applications of Tetrahydrofuran-Stable Substituted (3-Lithioxyalkyl)- and (4-Lithioxyalkyl)lithiums, Modified with Magnesium 2-Ethoxyethoxide
Kostas, Ioannis D.,Screttas, Constantinos G.
, p. 5575 - 5577 (2007/10/03)
Substituted hydroxyalkyl phenyl sulfides 3 have been synthesized from the corresponding allylic or homoallylic alcohols 2. Regiospecific cleavage of the C - SPh bond of the sulfides 3 by lithium dispersion in tetrahydrofuran (THF) led to the synthesis of substituted (3-lithioxyalkyl)- and (4-lithioxyalkyl)lithiums 4, most of which share the ω carbon with a carbocyclic ring. The organolithiums were modified with magnesium 2-ethoxyethoxide in order to suppress their reactivity toward THF cleavage, thus offering the advantage of preparing storable ethereal solutions of certain types of (lithioxyalkyl)lithiums. This strategy appears to be of rather broad scope. The functionalized organolithiums prepared in this way react normally with electrophilic reagents with yields in the range 35-55%. Thus, carboxylations of 4 yielded lactones 5, some of which are natural products, while reactions of 4 with benzophenone and cyclic ketones yielded 1,4- and 1,5-diols 6 and 7, respectively.
A new synthesis of lactones from tertiary alkenylcarbinols by cobalt-catalyzed photocarbonylation under ambient conditions
Chow, Yuan L.,Huang, Yu-Jin,Dragojlovic, Veljko
, p. 740 - 742 (2007/10/02)
In the presence of a Co catalyst, tertiary vinyl-, propenyl-, and allylcarbinols were chelatively cycloadded to carbon monoxide to produce lactones by xanthone-sensitized photoreaction in tetrahydrofuran, under CO at 1 atmosphere and at room temperature.At lower temperatures the isomerization of alkenyl-carbinols was suppressed and lactones were obtained with improved selectivity.The photoprocess was facilitated by addition of pyridine or hydrogen and retarded in presence of amines or phosphines.Mechanistic interpretations for the process and the accompanying effects are discussed.Key words: chelative carbonylation, photocarbonylation, carbonylation of olefins, lactones synthesis from alkenylalcohols.
DIRECT SYNTHESIS OF δ-LACTONES FROM 2-(3-LITHIOPROPYL)-1,3-DIOXOLANE AND CARBONYL COMPOUNDS
Ramon, Diego J.,Yus, Miguel
, p. 3767 - 3770 (2007/10/02)
The reaction of 2-(3-lithiopropyl)-1,3-dioxolane (2), prepared in situ by lithiation of the chloroacetal 1 with lithium naphthalenide at -78 deg C, with aldehydes and ketones followed by hydrolysis with hydrochloric acid and final oxidation with PCC or Jones reagent yields the corresponding δ-lactones 5.
The Key Role of Water in the Heterogeneous Permanganate Oxidation of ω-Hydroxy Alkenes
Baskaran, Sundarababu,Islam, Imadul,Vankar, Padma S.,Chandrasekaran, Srinivasan
, p. 1670 - 1671 (2007/10/02)
Potassium permanganate-copper sulphate in dichloromethane in the presence of a catalytic amount of water effects a smooth oxidative cyclization of ω-hydroxy alkenes to ω-lactones in good yields with the net loss of one or more carbon atoms in the procees.
NEW ORGANOCOPPER REAGENTS PREPARED UTILIZING HIGHLY REACTIVE COPPER
Rieke, Reuben D.,Wehmeyer, Richard M.,Wu, Tse-Chong,Ebert, Greg W.
, p. 443 - 454 (2007/10/02)
Highly reactive copper solutions have been prepared by the lithium naphthalide reduction of copper(I) iodide/trialkylphosphine complexes.These activated copper solutions will react with organic halides under very mild conditions to form stable organocopper reagents.Significantly, the organocopper reagents can contain considerable functionalities such as ester, nitrile, chloride, epoxide, and ketone groups.These functionalized organocopper species undergo many reactions typical of other organocopper species.Intermolecular 1,4-additions, epoxide-opening reactions, and ketone formation with acid chlorides have been successfully achieved.In addition, this methodology has been applied to an intramolecular epoxide-cleavage reaction.The influence of the connecting chain length, substitution pattern, reaction solvent, and CuI/phosphine complex upon the regioselectivity of the intramolecular cyclization is described.
DIRECT FORMATION OF EPOXYALKYLCOPPER REAGENTS FROM ACTIVATED COPPER AND EPOXYALKYL BROMIDES AND THEIR INTRAMOLECULAR CYCLIZATIONS
Wu, Tse-Chong,Rieke, Reuben D.
, p. 6753 - 6756 (2007/10/02)
Epoxyalkylcopper compounds have readily been prepared by the direct oxidative addition of active copper to epoxyalkyl halides.The intramolecular cyclization of the epoxyalkylcopper reagents via an epoxide cleavage process is described.Significantly, many functional groups can be present in the bromoepoxides yielding highly functionalized carbocycles.The regioselectivity of this cyclizations is affected by the connecting chain length, substitution pattern, reaction solvent, and the CuI-phosphine complex used to generate the copper.
SUBSTITUENT DIRECTED OXIDATIVE CYCLIZATION WITH CETYLTRIMETHYLAMMONIUM PERMANGANATE: A GENERAL APPROACH TO THE SYNTHESIS OF γ- AND δ-LACTONES
Rathore, Rajendra,Vankar, Padma S.,Chandrasekaran, S.
, p. 4079 - 4082 (2007/10/02)
Treatment of primary, secondary or tertiary γ- and δ-hydroxyolefins with cetyltrimethylammonium permanganate gives good yields of γ- and δ-lactones by oxidative cyclization, with loss of one carbon.
A HIGHLY EFFICIENT SYNTHESIS OF γ- AND δ-LACTONES BY OXIDATIVE CYCLIZATION
Chakraborty, T. K.,Chandrasekaran, S.
, p. 551 - 554 (2007/10/02)
Treatment of tertiary γ- and δ-hydroxyolefins with pentavalent chromium reagent, (BipyH2)CrOCl5, give good yields of γ- and δ-lactones by oxidative cyclization, with loss of one carbon.Pyridinium chlorochromate (PCC) also effect this transformation to γ-lactones in reasonable yields.
One-Step Spiroannelation. Synthesis of Spiro γ- and δ-Lactones
Canonne, Persephone,Belanger, Denis,Lemay, Gilles,Foscolos, Georges B.
, p. 3091 - 3097 (2007/10/02)
Carbocyclic acid anhydrides can be converted to spiro γ- and δ-lactones by addition of di-Grignard reagents in tetrahydrofuran solution.Five- and six-membered rings have been formed in one-step reactions.Possible mechanistic pathways for this reaction are discussed.The conversion of spirolactones to 1-(ω-hydroxyalkyl)cycloalkanols was accomplished by reduction with LAH to illustrate the versatility of these substances giving (after or upon treatment with tosyl chloride) the corresponding spiroethers.
