Z-Selective Hydrosulfoxidation of Alkynes with Thiols and Hydrogen Peroxide Enabled by a Multifunctional Octamolybdate

Abstract

Although sulfoxide is an important structural motif found in biological molecules and prevalent feedstocks in synthetic chemistry, a general and sustainable access route to (Z)-α,β-unsaturated sulfoxides remains highly challenging  due to the thermodynamic instability of Z-type geometric and the notorious sulfur nucleophiles poisoning of metal catalyst.  Here we report a new protocol based on homogeneous octamolybdate-catalyzed anti-hydrothiolation and after Z-retentive sulfoxidation methodology, allowing access to (Z)-α,β-unsaturated sulfoxides from commercially available alkynes, thiols and H2O2. Control experiment investigations indicate that the molecular molybdenum is a thiyl radical initiator, Z-type geometric mediator and sulfoxidation catalyst. Notably, this one-pot reaction features broad substrate scopes with high stereoselectivity (Z/E up to >99:1) and mild reaction conditions, thus providing a promising approach for the preparation of Z-vinyl sulfoxide compounds.

Keywords: Polyoxometalates，Z-Selectivity，C-S Coupling，Hydrosulfoxidation，Selectve Oxidation