Unsaturated adds

Te various compounds Various alcohols and adds Unsaturated adds 68,174... 

Ethyl-2-methyl-2-octenoic acid has been prepared only by this method. An alternate synthesis of a-alkyl-a,fl-unsaturated adds proceeds via a-bromination of the saturated acid, followed by dehy-drohalogenation with quinoline at elevated temperatures.11 The present method is especially well adapted to preparation of a/y-dialkyl-a,j3-unsaturated acids. 

Bromopropiophenone from aluminum chloride catalyzed bromination of propiophenone, 40, 9 3-Bromo-4-tolualdehyde from aluminum chloride catalyzed bromination of J>-tolualdehyde, 40, 9 sec-Butyl acrylate, 41, 62 sec-Butyl alcohol, esterification of cro-tonic add with, 41, 60 esters with a,/3-unsaturated adds, 41, 62... 

Various trifluoromethyl containing a,(3-unsaturated adds, esters, ketones, and nitriles have been used as dienophiles Details regarding regiochemistry and stereochemistry have been reported [28, 98, 99] (equations 82-84)... 

The presence of two or more carboxyl groups in a carbon chain gives rise to dicarboxylic, tricarboxylic, etc., adds many of these acids are designated by universally recognised and accepted trivial names (see Table 10.20). Unsaturated adds are considered in Section 5.18.3, p. 804 other functionally substituted acids (e.g. hydroxy acids, amino adds, etc.) are considered in Section 5.14. 

Benzenesulfenyl chloride can convm unsaturated adds to lactones. The unsatuiated add (7) is treated with benzenesulfenyl chloride, followed by Raney nickel, to afford the 7-lactone (8) in excdlent overall yield (equation 5). Another acid (9) has been lactonized to produce the spiro-p-lactone (10) whidi rearranges on silica gel to 7-lactone (11 equation 6). 6-Lactones have been also prqrared using diis rq>-proach. An additional advantage of this approach is that the phenyl sulfide moiety can be manipulated into a variety of functional groups to facilitate cyclization. in suirunary, successfiil cyclization reactions... 

Reaction of a,P-unsaturated acids with ketones Lithium naphthalenide in the presence ofdiethylamine reacts with x,/ -unsaturated adds, for examplecrotonic acid (1), to give the a-anion of lithium crotonate. This anion reacts with ketones, for example cyclohexanone (2), to give d-hydroxy acids, for example 5(r-hydroxycyclohex-r-yl)-crotonic acid (3). 

A number of polymer latices falling into this category have been described in the literature bot they are still relatively novel and have not received the extensive attention given to the more conventional latices. Probably the systems of this type most extensively characterized are those described by Hoy (1979) and Bassett and Hoy (1980) which were prepared by copolymerizing methyl methacrylate, butyl acrylate, and ethji acrylate with an unsaturated add such as itaconic, aciyh c, or methylacrylic. The particles obtained appeared to consist of a spherical core particle sur-... 

Reduction to the alcohol or to the unsaturated add or ketone would give the right oxidation level and could occur as the chain is built, after it is completed, or after cyclization. In fact, reduction to... 

Carboxylic acid groups can be detected by both and C NMR spectroscopy. Carboxyl carbon atoms absorb in the range 165-185 6 in the C NMR spectrum, with aromatic and a,/3-unsaturated adds near the upfield end of the range (--les 8) and saturated aliphatic acids near the downfield end (-185 8). The acidic -COOH proton normally absorbs as a singlet near 12 8 in the H NMR spectrum. As with alcohols (Section 17.12), the -COOH proton can be replaced by deuterium when D2O is added to the sample tube, causing the absorption to disappear from the NMR spectrum. 

The reactions taking place in the formation of the alkylenes as well as those in the formation of addition products are not only applicable to the hydrocarbons but also to their substitution products. Thus, e.g., unsaturated adds are commonly obtained from oxyadds by the elimination of water ... 

The expected cycloaddition of ,[i-unsaturated add chloride and chloral indeed occurred in the presence oftertiary amine. The yields could be significantly improved by adding a Lewis acid cocatalyst, Sn(OTf)2, which would facilitate the deprotonation of acid chloride and activate the aldehyde substrate. More satisfactory results could be obtained when acid chloride was added slowly by syringe pump to avoid massive... 

TroHxsterifiealhn. Methyl esters of nromatic and a, p>unsaturated adds (an undergo transesterirication when treated with an alcohol (excess) and BuU (1 equiv.) in dry THF at 25 (equation 1). The yields can be quantitative in reactions... 

From Achiral Non-carbohydrates. - Epoxide 57, available from methyl sorbate by a chemoenzymatic synthesis (Ono et ai, Tetrahedron Asymmetry, 1996, 7, 2595), was used in the construction of a set of isomeric 3-amino-2,3,6-trideoxyhexoses. Addition of benzylamine to the a,p-unsaturated add moiety before or after opening of the epoxide ring led to the D-acosamine derivative 58 or the lactone 59, respectively (Scheme 17)." Lactone 59 has previously been converted to L-daunosamine and D-acosamine derivatives (Vol. 14, p. 72, ref. 14). 

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