Complete control of chemo-, regio- and stereoselectivity in the course of copper-catalyzed and -mediated allylic substitution could be obtained with the ortho-diphenylphosphanyl (o-DPPB) function as a reagent-directing leaving group. Complete chirality transfer by way of a syn-addition process has been achieved for cyclic and acyclic systems. Readily available Grignardreagents may be employed as nucleophiles