3,8-Nonadienoic acid

When alkadienoic acids were hydrogenated with [RhCl(PPh3)3] or [RhCl P(p-tolyl)3 3] catalysts an unusual effect of water was observed [65]. In dry benzene, hydrogenation of 3,8-nonadienoic acid afforded mostly 3-nonenoic acid. In sharp contrast, when a benzene-water 1 1 mixture was used for the same reaction the major product was 8-nonenoic acid with only a few % of 3-nonenoic acid formed. Similar sharp changes in the selectivity of hydrogenations upon addition of an aqueous phase were observed with other alkadienoic acids (e.g.3,6-octadienoic acid) as well. 

The hydroesterification of dienes gave both the unsaturated monoesters and saturated diesters.524 In some cases, y-ketoesters were obtained and carbonylation of 1,5-cyclooctadiene in absence of alcohol gave a ketone.525 [PdI2(PBu3)2] was used as catalyst. If the catalyst contained a halide anion, butadiene underwent normal hydroesterification. When halide-free catalysts were used, the reaction took a different course. Dimerization of the diene occurred to give the ester of 3,8-nonadienoic acid as the major product (equation 128).526-528... 

Butadiene reacts with carbon monoxide and alcohols - or amines to form 3,8-nonadienoic acid derivatives. A variety of alcohols, even relatively bulky ones, can be used. For example, reaction of butadiene with CO (50 atm) in tm-butyl alcohol (Pd(OAc)2/4 Ph3P, 110 °C, 16 h) affords the /3,y-unsaturated tm-butyl ester 141 in 92% yield (Scheme 45). CO pressures greater than 50 atm slow the reaction as do Ph3P/Pd ratios greater than or less than 4 1. 

The importance of unsaturation is illustrated by the fact that 2,4-nonadienoic acid [21643-39-0] forms a Hquid crystal phase, whereas the aHphatic carboxyHc acids do not. The two double bonds enhance the polarizabiHty of the molecule and bring iatermolecular attractions to a level that is suitable for mesophase formation. The overall linearity of the molecule must not be sacrificed ia poteatial Hquid crystal candidates. For example, whereas /n j - -aIkoxyciaaamic acids (5) are mesomorphic, the cis isomers (6) are not, a reflection of the greater anisotropy of the trans isomer. 

Nonadienoic acid, 4-methyl-, trans, ethyl ester, 53, 116 Nonan-5-ol, 52, 22 D-NORANDROST-5-EN-36-0L-16-CARBOXYLIC ACIDS, 52, 53 Norbornene, with ethyl tri-... 

Nonadienoic acid, 4-methyl, trans, ethyl ester)... 

REGIO- AND STEREOSELECTIVE CARBOXYLATION OF ALLYLIC BARIUM REAGENTS (E)-4,8-DIMETHYL-3,7-NONADIENOIC ACID... 

The checkers performed this procedure on five times the reported scale and obtained 2.6 g (41%) of crude (impure) (E)-4,8-dimethyl-3,7-nonadienoic acid following chromatographic purification. 

The next four procedures all involve the preparation of useful olefin derivatives. p.y-Unsaturated carboxylic acids such as (E)-4,8-DIMETHYL-3,7-NONADIENOIC ACID are important intermediates for many natural products syntheses. Allylic barium... 

Regio- and Stereoselective Carboxylation of Allylic Barium Reagents (E)-4,8-Dimethyl-3,7-nonadienoic Acid. 

C-18 JH, ClflHttOj, 7-ethyl 9A3 thyl 3 methytoxiranyt) 3-methyl-2,6-nonadienoic acid methyl ester cis-i0,ll-epoxy- -ethyl-3,II-dimethyl-trans,trans-2,6-tridecadienoic acid methyl cis-10,11 -oxido-3, Il-di methyl-7-ethyltrideca-tra ns, tranS 2,6-dienoate. R = C2HV C-17 JH, C HjjOj, cis-10,11 -epoxy-3,7,11-trimethyb trans,irans.Z,6-tridecadienoic acid methyl ester. R — CHj. 

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