Diradical-Promoted (<i>n </i>+ 2 − 1) Ring Expansion: An Efficient Reaction for the Synthesis of Macrocyclic Ketones
作者:Georg Rüedi、Matthias A. Oberli、Matthias Nagel、Hans-Jürgen Hansen
DOI:10.1021/ol048701e
日期:2004.9.1
[reaction: see text] A diradical-promoted (n + 2 - 1) ringexpansionreaction based on vinyl side chain insertion (+2C) and decarbonylation (-1C) has been developed. Flash vacuum pyrolysis (FVP) of medium- and large-ring 2-trimethylsilyloxy-2-vinyl-cycloalkanones at 500-600 degrees C affords the one-carbon ring-expanded cycloalkanones in good yields. Methyl groups on the vinyl moiety are transformed
Ring enlargement through acyloin condensation of cycloalkane-1,2-dicarboxylic esters
作者:T. Mori、T. Nakahara、H. Nozaki
DOI:10.1139/v69-540
日期:1969.9.1
13-membered rings were prepared from cyclododecanone. Acyloincondensation of these esters in the presence of trimethylchlorosilane followed by acidic hydrolysis afforded 13-, 14-, and 15-membered cycloalkane-1,2-diones in 71–74% yields. The diketones were reduced by treatment with triethyl phosphite and alkali hydroxide into corresponding acyloins.
A method for purifying a macrocyclic ketone is disclosed which comprises light-irradiating a macrocyclic ketone containing a macrocyclic diketone as an impurity. Preferably, the macrocyclic ketone as light-irradiated is treated with an active charcoal so as to elevate the purity of the resulting macrocyclic ketone. For light-irradiation, the macrocyclic ketone may be in the form of an alcohol solution.