Z-Selective hydrosulfoxidation of alkynes with thiols and hydrogen peroxide Enabled by a Multifunctional octamolybdate

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.