the diasteromeric adducts are (2S,3R,3R')-(-)-4-(4-Bromophenyl)-3-hydroxy-2-(1,7,7-trimethylbicyclo[2,2,1]heptan-2-on-3-yl)-4-oxobutanoic acid and (2R,3S,3R')-(+)-4-(4-Bromophenyl)-3-hydroxy-2-(1,7,7-trimethylbicyclo[2,2,1]heptan-2-on-3-yl)-4-oxobutanoic acid