RCsumC. La radioreduction y de cyclohexanones substituees conduit principalement aux deux cyclohexanols diastereoisomeres correspondants. La stkreoselectivite de cette reaction depend de la concentration en cetone. L'existence de deux radicaux pyramidaux diasttrtoisomeres, precurseurs des cyclohexanols, est a I'origine des stkrtostlectivites observkes. Un processus de solvatation selective de I'OH radicalaire a ete propose pour rendre compte des variations de stertosklectivitk avec la concentration en cetone.Abstract. y Radioreduction of substituted cyclohexanones mainly leads to diastereoisomeric cyclohexanols. The stereoselectivity of radioreduction depends on ketone concentration. The assumption of two pyramidal diastereoisomeric hydroxycyclohexyl radicals explains the observed stereoselectivity. A selective solvation process of the hydroxy group of the radical has been proposed to account for the variations of stereoselectivity with ketone concentration.