Syn-Selective anti-Markovnikov Intramolecular Hydroamination

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).