Z‐Selective Hydrothiolation of Racemic 1,3‐Disubstituted Allenes: An Atom‐Economic Rhodium‐Catalyzed Dynamic Kinetic Resolution |
| |
Authors: | Adrian B Pritzius Prof?Dr Bernhard Breit |
| |
Institution: | Institut für Organische Chemie, Albert‐Ludwigs‐Universit?t Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau (Germany) |
| |
Abstract: | A Z‐selective rhodium‐catalyzed hydrothiolation of 1,3‐disubstituted allenes and subsequent oxidation towards the corresponding allylic sulfones is described. Using the bidentate 1,4‐bis(diphenylphosphino)butane (dppb) ligand, Z/E‐selectivities up to >99:1 were obtained. The highly atom‐economic desymmetrization reaction tolerates functionalized aromatic and aliphatic thiols. Additionally, a variety of symmetric internal allenes, as well as unsymmetrically disubstituted substrates were well tolerated, thus resulting in high regioselectivities. Starting from chiral but racemic 1,3‐disubstituted allenes a dynamic kinetic resolution (DKR) could be achieved by applying (S,S)‐Me‐DuPhos as the chiral ligand. The desired Z‐allylic sulfones were obtained in high yields and enantioselectivities up to 96 % ee. |
| |
Keywords: | allenes asymmetric catalysis dynamic kinetic resolution rhodium sulfones |
|
|