Thiiranes: reductive desulfurization

The progress on S-C bond activation, which covers the reduction of a C-S bond to a C-H bond, cross coupling reaction of sulfides with main group organometaUic nucleophiles, ring opening reactions of thietanes and thiiranes, and desulfurization of thiols, sulfides, and thiophenes has already been reviewed elsewhere [6-10], and... 

The reductive desulfurization of thiiranes has been accomplished with Raney nickel, Li in EtNHa, Zn in HOAc, BusSnH, and P2I4 in DMF but the reaction has seldom been applied to organic synthesis. A noteworthy procedure for preparing moderately hindered tetrasubstituted alkenes, which proceeds via a thiirane intermediate, was developed independently by Barton and Kellogg. The procedure, illustrated in Scheme 14 for the preparation of (34), involved reaction of thiocamphor (30) with diazoalkane... 

Thioamides of two cyclopropanecarboxylic acids undergo coupling reactions with diazomethane derivatives in refluxing benzene containing rhodium(II) acetate. The reaction conceivably takes place via a thiirane intermediate which undergoes reductive elimination by reaction with excess diazo compound. An example of an intramolecular reaction is the formation of indolizine 2. If the diazo compound is not in excess a thiol is formed, this can be removed by Raney nickel desulfurization. ... 

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