title: Z-Selective Hydrothiolation of Racemic 1,3-Disubstituted Allenes: An Atom-Economic Rhodium-Catalyzed Dynamic Kinetic Resolution.
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.
authors.affiliation: Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau (Germany).
authors.forename: Adrian B
authors.initials: AB
authors.lastname: Pritzius
authors.affiliation: Institut für Organische Chemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg im Breisgau (Germany). bernhard.breit@chemie.uni-freiburg.de.
authors.forename: Bernhard
authors.initials: B
authors.lastname: Breit
keywords: allenes; asymmetric catalysis; dynamic kinetic resolution; rhodium; sulfones