Cyclopentanecarboxylic acids methyl ester

Cyclohexylmethylpropiolaldehyde diethyl acetal, 39, 60 1,2-Cyclononanedione, 36, 78 Cyclopentadiene, 32, 41 36, 32, 35 Cyclopentanecarboxylic acid, METHYL ESTER, 39, 37 Cyclopentanol, 2-chloro-, irans-,... 

C8H14O3 cis-2-methoxy-cyclopentanecarboxylic acid methyl ester 54108-61-1... 

CONJUGATE ADDITION/CYCLIZATION OF A CYANOCUPRATE 2-CARB0METH0XY-3-VINYLCYCL0PENTAN0NE (Cyclopentanecarboxylic acid, 2-ethenyl-5-oxo-, methyl ester)... 

The methyl ester has also been obtained by esterification of cyclopentanecarboxylic acid.8 The acid, in turn, has been prepared by the Favorskii rearrangement,6 7 9-11 by the reaction of cyclopentyl Grignard reagent with carbon dioxide,12 by the carbonylation of cyclopentyl alcohol with nickel carbonyl13 or with formic acid in the presence of sulfuric acid,14 and by the hydrogenation of cyclopentene-1-carboxylic acid prepared from ethyl cyclopentanone-2-carboxylate 15 or from cyclopentanone cyanohydrin.16... 

When one attempts E2 reactions with a-halo ketones using strong bases such as alkoxides, an interesting rearrangement pathway may occur called the Favorskii rearrangement. In this reaction, the a-halo ketone is converted to an ester. For example, 2-chlorocyclohexanone is converted to the methyl ester of cyclopentanecarboxylic acid by treatment with sodium methoxide in ether ... 

The rearrangement of cyclic ketones involves ring contraction. Thus, 2-chlorocyclobutanone (2.29) on treatment with sodium methoxide followed by hydrolysis is converted into cy-clopropanecarboxylic acid (2.30). In a similar manner, 2-bromocyclohexanone (2.31) on treatment with sodium methoxide gives methyl ester of cyclopentanecarboxylic acid (2.32). 

Problem 7.13. When 2-chlorocyclohexanone-2- C is treated with sodium methoxide in methanol, labeled methyl cyclopentanecarboxylate results. Careful degradation of the carboxylic acid ester (Chapter 9) showed that the location of the position of the labeled carbon was restricted to three carbon atoms, (a) On which three carbons is the label found (b) What is the distribution of the label (i.e., what percent of the label is found at each carbon) ... 

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