69604-12-2

Upstream product

• 128071-66-9 3-[1-Chloro-meth-(E)-ylidene]-4,4,5,5-tetramethyl-dihydro-furan-2-one 
• 127091-16-1 (3E)-dihydro-3-(iodomethylene)-4,4,5,5-tetramethyl-2(3H)-furanone 
• 72163-32-7 [4,4,5,5-Tetramethyl-2-oxo-dihydro-furan-(3Z)-ylidene]-acetic acid 
• 77613-25-3 (4,4,5,5-Tetramethyl-2-oxo-tetrahydro-furan-3-yl)-acetic acid 
• 72163-16-7 dimethyl-3,3,4-trimethyl-1,4-pentadiene-1,2-dicarboxylate 
• 72163-26-9 (E)-dihydro-3-carbomethoxymethylene-4,4,5,5-tetramethyl-2(3H)-furanone 
• 72163-23-6 (Z)-dihydro-3-carbomethoxymethylene-4,4,5,5-tetramethyl-2(3H)-furanone 
• 563-79-1 2,3-Dimethyl-2-butene 
• 128071-73-8 5-Chloro-4,4,5-trimethyl-hex-2-ynoyl chloride 
• 128071-60-3 4-Chloro-2-[1-chloro-meth-(E)-ylidene]-3,3,4-trimethyl-pentanoic acid 
• 113426-68-9 2-Chloro-3-(2-chloro-1,1,2-trimethyl-propyl)-cycloprop-2-enone 
• 113426-63-4 1,3,3-Trichloro-2-(2-chloro-1,1,2-trimethyl-propyl)-cyclopropene 
• 77613-26-4 (4,4,5,5-Tetramethyl-2-oxo-tetrahydro-furan-3-yl)-acetic acid methyl ester 
• 118652-84-9 2-Bromo-2,3-dimethyl-3-<(2-bromo-1-methoxy-2-propen-1-yl)oxy>butane 

Relevant academic research and scientific papers

ALKYLIDENE LACTONE SYNTHESIS

The iodoalkylidene lactones formed by reaction of alkenes with acetylenic acids in the presence of N-iodosuccinimide and subsequent free radical cyclisation, can be de-iodinated photochemically or alkylated with lithium diorganocuprate reagents to yield a variety of α-alkylidene lactones.

Regio- and stereoselective ring-opening reactions of cyclopropenones: α-methylene-γ-butyrolactones via additions of trichlorocyclopropenylium ions to alkenes

The 2-chloro-3-(2'-chloroalkyl)cyclopropenones 4, readily obtained by hydrolysis of the adducts of the trichlorocyclopropenylium ion onto alkenes, thermally rearrange to propiolic acid chlorides 6. Treatment of 4 with TosOH·H2O in CH2/sub

DE-IODINATION AND ISOMERISATION OF IODOALKYLIDENE LACTONES

The (E)-iodoalkylidene lactones which can be formed by reaction of an alkene with N-iodosuccinimide and an acetylenic acid with subsequent free-radical cyclisation, are readily transformed into iodine free akylidene lactones by photolysis.Under different reaction conditions, the photolyses yield mixtures of (E) and (Z)-iodovinylidene lactones.

A New Synthetic Route to β-Bromoprop-2-ynyl Mixed Acetals and Bromovinyl Bis-allyl Mixed Acetals, Precursors of α-Methylene-γ-Butyrolactones

Cohalogenation by N-bromosuccinimide in methanol of β-bromoallenyl ethers (3a-g) or allyl allenyl ethers (8d-f) affords unsaturated halogeno-compounds (5a-g) or (9d-f) which are converted via homolytic carbocyclization into α-methylene-γ-butyrolactones (7a-g).

APPLICATIONS OF THE ENE REACTION. SYNTHESIS AND PROPPERTIES OF SUBSTITUTED &α-METHYLENE-&γ-LACTONES

Substituted dimethyl 1,4-pentadiene-1,2-dicarboxylates ( 1 or 3 ) may be prepared by AlCl3-promoted or thermal ene reaction of olefins with dimethyl acetylenedicarboxylate.Lactonization of these adducts is catalyzed by acid.In the presence of 80 percent H2SO4 the predominant product ( ca. 80 percent ) is a (Z)-dihydro-3-carbomethoxymethylene-2(3H)-furanone ( 2 or 4 ).Cyclization with anhydrous HCl affords a mixture of products the composition of which depends on the starting material; major products include the corresponding (E)- and γ-lactone isomers ( 6 and 7 ).Detailed 1H and 13C nmr are reported for all compounds.The structures of the (E)-4,5,5-trimethyl-, (Z)-4,5,5-trimethyl-, and (Z)-4,4,5,5-tetramethyl furanone derivatives ( 6a, 2a, and, 2b,) have been established by X-ray crystallography.The properties of some of these lactones are discussed, as are possible methods of removal of the carbomethoxyl from 2.

A new synthesis of substituted α-methylene-γ-lactones

Ene reactions of suitably substituted olefins with dimethyl acetylenedicarboxylate give substituted 1,4-pentadiene-1,2-dicarboxylates, which undergo acid-catalyzed cyclization to α-carbomethoxymethylene γ-lactones.