AZ-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 functionalizeda romatic and aliphatic thiols.A dditionally,avariety of symmetric internal allenes,a sw ell as unsymmetrically disubstituted substrates were well tolerated, thus resulting in high regioselectivities.S tarting from chiral but racemic 1,3-disubstituted allenes adynamic 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.Recently we described several highly selective methods for the addition of pronucleophiles to terminal allenes [1,2] and alkynes, [3] which can be regarded as atom-economic [4] alternatives to known allylic substitutions [5] and allylic oxidations. [6] In this respect we developed the first asymmetric hydrothiolation [7] of free aromatic and aliphatic thiols to terminal allenes to obtain branched allylic thioethers,a nd after oxidation, the corresponding allylic sulfones with excellent regio-and enantioselectivities (Scheme 1). [8] Since many bioactive compounds such as Montelukast, [9a] Hepatitis Cvirus NS3/4A inhibitors, [9b] and others [9c-e] include a-stereogenic C À Sb onds,t he synthesis of higher-substituted allylic thioethers [10,11] and sulfones [12,13] could be seen as an important synthetic tool in organic chemistry [14,15] and drug synthesis.F urthermore, a-stereogenic allylic Z-configured thioethers showed activity against allergic asthma and other immediate hypersensitivity diseases.[16] Thus we were curious to see whether we could transfer our initial methodology to 1,3-disubstituted allenes.H erein we describe the first rhodium-catalyzed, highly Z-selective and, if desired, asymmetric, hydrothiolation of 1,3-disubstituted allenes.A fter optimization of the reaction conditions using naphthalene-2-thiol and nona-4,5-diene with addition of p-toluenesulfonic acid (PTSA), the sulfone 1 was obtained in 80 %y ield and 91:9 Z selectivity (Table 1). [17][18][19] Furthermore,weinvestigated the scope of different aromatic thiols for this hydrothiolation. Applying thiophenol as as uitable nucleophile the sulfone 2 was obtained in moderate Z/E selectivity of 78:22. Thelower selectivity compared with naphthalene-2-thiol (1)s uggested that steric reasons are important for ah igh Z selectivity. Accordingly, Z selectivities increased when going from p-methylthiophenol (3;7 4:26) to o-methylthiophenol (5; 91:9). When using the sterically demanding naphthalene-1-thiol, the allylic sulfone 6 was obtained in excellent Z/E selectivity of 93:7.An umber of functionalized thiophenol derivatives were tolerated (7-12;T able 1). Especially,s ulfones with electronwithdrawing substituents gave excellent Z selectivities w...