3-methylbut-2-enoic acid

The preparation of 3-methyl-6-(2-methylpropenyl)pyran-2-one by the acid-catalyzed self-condensation of 3-methylbut-2-enoic acid has been described (B-68MI22400). 

Experiment 5.125 3,3-DIMETHYLACRYLIC ACID (3-Methylbut-2-enoic acid)... 

Racemic cis- and tran.s-nor-abscisic acid (132) and (133) have been prepared in five steps from the protected hydroxy-ketone (134) and the acetylene (135). Reaction between the dianion of 3-methylbut-2-enoic acid (136) and... 

Acrylic, 2-methylpropenoic and but-2-enoic acids do not form dichlorocyclopropanes using the chloroform/base/phase-transfer catalyst method, while 2-methylbut-2-enoic and 3-methylbut-2-enoic acids afforded products in low yield, e.g. formation of 1. " ... 

E.28) (E.28) 2-Butenoic acid, 3-methyl-, 3-methylbut-2-enoic acid, 3,3-dimethylacrylic acid, senecioic acid [541-47-9] FEMA 3187... 

By contrast, reaction of phloroglucinol with 3,3-dimethylacrylic acid (3-methylbut-2-enoic acid) in the presence of anhydrous aluminium chloride and phosphorus oxychloride by agitation during 5 hours at ambient temperature gave a 90% yield of 2,2-dimethyl-5,7-dihydroxychroman-4-one (ref.9). 

Unsaturated Acids.—Halogen-metal exchange occurs between 2-bromo-3-methylbut-2-enoic acid and n-butyl-lithium at — 100 C. The vinyl-lithium (17) so... 

The most frequently occurring carboxylic adds with five carbon atoms per molecule are (Z)-2-methylbut-2-enoic acid, also known as (Z)-2,3-dimethylacrylic or angelic acid, its isomer (E)-2-methylbut-2-enoic acid, known as ( )-2,3-dimethylacrylic (tiglic) acid, (Z)-3-methylbut-2-enoic acid (senecioic) acid (8-62) and (Z)-2-hydroxymethylbut-2-enoic (sarracinic) acid (10-14). 

The reaction of 2-bromo-6-lithiopyridine (13) with trialkylboranes gives intermediate boron compounds which are versatile intermediates for the preparation of unsaturated nitriles (Scheme 9). A stereospecific synthesis of dehydronerol utilizes the dianion of 3-methylbut-2-enoic acid as an isoprene functionality (Scheme 10). Lithium dianions from aj8-unsaturated acids generally undergo alkylation reactions at the a-carbon atom. In contrast the dicopper dianions undergo more selective y-alkylation (62—99%) and this ratio is generally higher than with the corresponding esters. A study of various acids and their alkylation with allyl electrophiles showed that allylic electrophiles unsubstituted at the y-carbon react... 

Hydroxycalamenal " is a sesquiterpenoid with a cadinene skeleton, isolated for the first time by extraction from the heartwood of dilferent types of elm Ulmus rubra and Uimus glabra)In 2005, Benincori Sannicolo, and co-workers proposed process-scale stereoselective synthesis of nature-identical ( )-(5, S)-7-hydroxycalamenal 222 via enantioselective hydrogenation reaction of 2-(4-methoxyphenyl)-3-methylbut-2-enoic acid 218 (Scheme 29.27). The homogeneous hydrogenation reaction... 

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