Thioboration of α,β-Unsaturated Ketones and Aldehydes toward the Synthesis of β‑Sulfido Carbonyl Compounds

Herein
a direct β-sulfido carbonyl compound synthesis by
the easy activation of RS−Bpin reagents with α,β-unsaturated
ketones and aldehydes is reported. This convenient methodology can
be performed at room temperature with no other additives. The key
point of this reactivity is based on the Lewis acidic properties of
the boryl unit of the RS−Bpin reagent interacting with the
CO oxygen. Consequently, the SR unit becomes more nucleophilic
and promotes the 1,4- versus the 1,2-addition, as a function of the
involved substrate. The thioborated products can be further transformed
into β-sulfido carbonyl compounds by addition of MeOH.