ChemInform Abstract: Stereospecific Synthesis of (+)- and (-)-Cyclooctenone Derivatives Using a Ring Expansion Reaction with Me3Si-SnBu3 and CsF.
Abstract
ChemInform is a weekly Abstracting Service, delivering concise information at a glance that was extracted from about 100 leading journals. To access a ChemInform Abstract of an article which was published elsewhere, please select a “Full Text” option. The original article is trackable via the “References” option.
ChemInform Abstract
A novel synthesis of cyclooctenones is presented utilizing a ring expansion reaction of cyclohexanones with a two carbon unit under the action of an in situ formed stannyl anion. Thus, cis- and trans-cyclooctenones are prepared from the corresponding mesyloxycyclohexanones containing a cis- or trans-iodoallyl side chain, resp., in the presence of Me3Si-SnBu3 and CsF. It is shown, that trans-cyclooctenones undergo trans—cis isomerization under the reaction conditions. The reaction proceeds stereoselectively. Thus, the use of an enantiomerically pure trans-cyclohexanone derivative (VII) enables the formation of optically active trans-cyclooctenone (VII). The reaction is also applicable to the synthesis of cycloheptenones [like (X)] from the corresponding cis-substituted cyclopentanones [cf. (IX)].
