By acyloin condensation

Tropolone has been made from 1,2-cycloheptanedione by bromination and reduction, and by reaction with A -bromosuccinimide from cyolo-heptanone by bromination, hydrolysis, and reduction from diethyl pimelate by acyloin condensation and bromination from cyclo-heptatriene by permanganate oxidation from 3,5-dihydroxybenzoic acid by a multistep synthesis from 2,3-dimethoxybenzoic acid by a multistep synthesis from tropone by chlorination and hydrolysis, by amination with hydrazine and hydrolysis, or by photooxidation followed by reduction with thiourea from cyclopentadiene and tetra-fluoroethylene and from cyclopentadiene and dichloroketene. - ... 

Civetonedicarboxylic acid was then converted into c/s-civetone (133) by acyloin condensation and the following steps (124) ... 

Acetaldehyde itself is transformed by entirely different mechanisms, partly by acyloin condensation, as was found in 1921, and partly by... 

Wynberg et al. have synthesized the interesting spiro[adamantane-2,l -cyclo-butane-2, 3 -dione] (8) from methyl 2(2-methoxycarbonyladamantyl)acetate (6) by acyloin condensation in the presence of trimethylchlorosilane to give the bis(trimethylsiloxy)cyclobutene derivative (7) in 75% yield. The key step, conversion of (7) into (8), was accomplished under non-hydrolytic conditions by addition of bromine to a solution of (7) in carbon tetrachloride.5... 

Methyl hydrogen azelate has been coupled to the l,w-Ci6-diester, which has been converted by acyloin condensation, deoxygenation and 1,4-addition of a methyl... 

An oxidative cleavage of cycloalkanones to unsaturated aldehyde-esters has been developed. Thus, for example, cyclononanone was converted into 2,2-dithio-trimethylenecyclononanone, which was cleaved using lead(iv) acetate (66 %), and the product so obtained treated with methanol and sodium periodate to give (208 in = 5). Cyclododecanone was similarly converted into (208 n = 8). 1,2-Bis(trimethyl-silyloxy)cycloalkenes, prepared by acyloin condensations, have been converted into 2-alkyl-2-hydroxycycloalkanones by treatment with methyl-lithium and an alkyl halide, and the oximes of these a-hydroxyketones cleaved to give open-chain co-cyanoketones using mesyl chloride-pyridine. ... 

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