A copper-catalyzed vicinal chloro-thiolation of alkynes with inexpensive and diversified sulfonyl chlorides RSO 2 Cl (R = aryl, alkyl) has been developed. This practical and scalable reaction could be used for the construction of a number of unexplored bioactive chlorothiolated alkenes. Internal alkynes could also undergo the chloro-thiolation to provide tetrasubstituted alkynes. Preliminary mechanistic investigations revealed a plausible radical process involving a sulfur-centered radical intermediate via copper-mediated homolysis of the S−Cl bond.
A practical and efficient method to synthesize thiocarbamyl fluorides and isothiocyanates from amines with trifluoromethanesulfonyl chloride was developed. In the presence of the reducing agent triphenylphosphine and sodium iodide, thiocarbamyl fluorides and isothiocyanates were synthesized from secondary/primary amine in moderate to excellent yields, respectively. A broad scope of substrates and good functional group compatibility were observed.
Newly developed sulfonyl chloride-based regioselective
chlorothiolation
of alkenes has been disclosed; the reaction is compatible with a variety
of functional groups and can be scaled up to the gram scale with no
loss in yield. The employment of readily available reactants, mild
reaction conditions, and high regioselectivity makes this process
very practical. Mechanistic studies revealed a possible free radical
reaction pathway.
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