This invention relates to compounds of the formula
wherein one of R5, R6 and R7 is
and X1, X2, Y1 to Y4, R1 to R13 and m and n are as defined in the description, and to all enantiomers and pharmaceutically acceptable salts and/or esters thereof. The invention further relates to pharmaceutical compositions containing such compounds, to a process for their preparation and to their use for the treatment and/or prevention of diseases which are modulated by PPARδ and/or PPARα agonists.