Rhodium-Catalyzed Regiodivergent Hydrothiolation of Allyl Amines and Imines

The regiodivergent Rh-catalyzed hydrothiolation of allyl amines and imines is presented. Bidentate phosphine ligands with larger natural bite angles (beta(n) >= 99 degrees), for example, DPEphos, dpph, or L1, promote a Markovnikov-selective hydrothiolation in up to 88% yield and >20:1 regioselectivity. Conversely, when smaller bite angle ligands (beta(n) <= 86 degrees), for example, dppbz or dppp, are. employed, the anti-Markovnikov product is formed in up to 74% yield and >20:1 regioselectivity. Initial Mechanistic investigations are performed and are, consistent with an oxidative addition/olefin insertion/reductive elimination mechanism for each regioisomeric pathway. We hypothesize, that the change in regioselectivity is an effect of diverging coordination spheres to favor either Rh-S or Rh-H insertion to form the branched or linear isomer, respectively.