Significance Using a Rh(I)/DPPB catalyst system, aminoolefins undergo a remarkably selective anti-Markovnikov hydroamination reaction to generate 3-arylpiperidines in good yields. When the aminoolefin is appropriately substituted (R ≠ H), products are obtained with high degrees of syn -selectivity; presumably due to equatorial placement of the substituents in a chair-like transition state. The N -methyl substituent is necessary for the reaction to proceed; however, this group can be easily cleaved (see scheme).