Carboxylic acids, vinyl esters

To a solution of 0.015 mmol aluminum catalyst with (/ )-6,6 -dibromo-3,3 -bis (diphenylphosphinoylmethyl)-2,2 -dihydroxy-l,l -binaphthyl as ligand in CH2CI2 was added 0.6 mmol l-methyl-isoquinoUne in 2.25 mL CH2CI2, followed by 160 ixL TMSCN (1.2 mmol) and 91.8 fiL vinyl chloroformate (1.08 mmol) at —60°C. After 48 h, the reaction was quenched by 5% NH3 aqueous solution, and extracted with EtOAc. Upon removal of solvent under reduced pressure, the reside was purified by column chromatography using hexane/EtOAc as the eluent to afford 91% (+)-l-cyano-l-methyl-l,2-dihydroisoquinoline-2-carboxylic acid vinyl ester as a colorless oil, with 84% e.e. as determined by chiral HPLC analysis. 

Moreover, in 1998 Ube Industries, Ltd. discovered that PC decomposition is suppressed by small quantities of additives (carboxylic acid vinyl esters, such as vinyl acetate (7) and divinyl adipate (8) vinyl carbonates, such as methyl vinyl carbonate (9) [50] carboxylic acid allyl esters, such as allyl acetate (10) allyl carbonates, such as allyl methyl carbonate (11) [51] and cyclic vinyl esters, such as a-angelica lactone (12) [52]). 

AUTONOM 6-Acetyl-3-(2-(3-lttert -butyl-phenyl)-ethylidene)-l-(2-fluoro-2-phenyl-thyl)-5-(8-nethyl-octahydro 2,5-nethano-isoqui olin-3-yl)-7 thioacryloyloxy-2, dihydro-l H pyrrolo[3,2 ltb ]pyridine-2 carboxylic acid vinyl ester... 

Carboxylic acid vinyl esters GOOH GOOGH GHg... 

The EVA polymer emulsions contain crystalline segments resulting from ethylene linkages. In addition to ethylene and vinyl acetate, a carboxylic comonomer is used, such as acrylamide or versa tic acid vinyl ester. The polymers have crystalline melting point of 50-90°C. 

For electron-poor alkynes (Scheme 2) such as acetylene carboxylic acid ethyl ester 4, the activated Au(III) catalysts lead to about 60% of the product 5 as a 3.6 1 Z/E mixture. In contrast, Au(I) complexes of phosphines activated by AgSbF6 or Lewis acids are much better suited, delivering nearly quantitative yields of 5 with complete Z-selectivity (Scheme 4) [2], Only traces of the doubly vinylated compound 6 are observed as a side product. A particularly effective Lewis acid is BF3 OEt2, which also makes the catalytic system cheaper than those using AgSbF6 as the activating agent. 

Preparation of 4-trifluoromethyl-2-vinyl-thiazole-5-carboxylic acid ethyl ester... 

Iron(III) 2-ethylhexanoate is a catalyst for the stereoselective hetero-Diels-Alder reaction of ethyl ( )-4-oxobutenoate with alkyl vinyl ethers to give ci5 -2-alkoxy-3,4-dihydro-2//-pyran-4-carboxylic acid ethyl esters with a high diastereoselectivity (Sch. 57) [203],... 

Based on the 13C-NMR shifts, one can surmise that the electronic effect of the substituent on the C = C bond is minimal. Thus, the vinyl carbons of the norbornene resonate at 135.5 ppm, while those of 5-norbornene-2-carboxylic acid ethyl ester appear at 137.7 and 132.5 ppm (endo) and 138.1 and 135.9 ppm (exo). 

A number of cycloaddition reactions involving allene derivatives as dienophiles have been recorded. Allene itself reacts only with electron-deficient dienes but allene carboxylic acid or esters, in which a double bond is activated by conjugation with the carboxylic group, react readily with cyclopentadiene to give 1 1 adducts in excellent yield. For example, the allene 12 gave, with very high yield and selectivity, the cycloadduct 13, used in a synthesis of (-)-P-santalene (3.19). An allene equivalent is vinyl triphenylphosphonium bromide, which is reported to react with a number of dienes to form cyclic phosphonium salts. These can be converted into methylene compounds by the usual Wittig reaction procedure (3.20). 

Synonyms Acetic acid, ethenyl ester Acetic acid, ethylene ether Acetic acid, vinyl ester 1-Acetoxyethylene Ethanoic acid, ethenyl ester Ethenyl acetate Ethenyl ethanoate VAc VAM Vinyl acetate, inhibited Vinyl acetate monomer Vinyl ethanoate Ciassiflcation Unsaturated carboxylic acid ester Empiricai C4H6O2 Formuia CH3COOCH=CH2 Properties Colorless liq. char, odor polymerizes in light to a colorless transparent mass sol. 1 g/50 ml water (20 C) sol. in ethanol, ether, acetone, benzene, chloroform, mostorg. soivs. m.w. 86.09 dens. 0.932 (20/4 C) vapor pressure 100 mm (21.5 C) m.p. -93 C b.p. 71-73 C flash pt. (CC) -8 C... 

The main process that occurs in silicones that contain vinyl groups is photo-scission. Also, the vinyl groups are photo-oxidized into silanols, carboxylic acids, and esters. Part of the silanols are condensed into high molecular weight silicones [585]. 

Acylketenes l-(AIkoxy)enolethers a-Alkoxymethyleneketones Carboxylic acid isopropenyl esters Enolesters Enollactols Enollactones a, p-Ethyleneacetals a,0-Ethylenelactones a-Hydroxymethyleneketones 3-Keto-l, 2-en-l-olethers 3-Keto-l,2-en-l-ols a-Oxidoalcohols a,P-Oxidoketones Vinyl esters... 

---