Mercaptoles desulfurization

Most frequently mercaptoles (dithioketals) are desulfurized to hydrocarbons... 

Nickel prepared by reduction of nickel chloride with sodium borohydride was used for desulfurization of diethyl mercaptole of benzil. Partial desulfurization using 2 mol of nickel per mol of the mercaptole gave 71% yield of ethylthiodesoxybenzoin while treatment with a 10-fold molar excess of nickel over the mercaptole gave 61% yield of desoxybenzoin (benzyl phenyl ketone) 937. ... 

Mercaptoles of ketones are best prepared by treatment of ketones with ethanedithiol or 1,3-propanedithiol in the presence of anhydrous zinc chloride or boron trifluoride etherate. Many desulfurizations have been carried out with these cyclic mercaptoles, especially in steroids. Yields of the hydrocarbons range from 50 to 95% [797]. 

Alternative desulfurizations can be achieved using tributylstannane or hydrazine. Reaction with the former reagent is carried out by heating the mercaptole for 1.5 hours at 80° with 3-4 equivalents of tributylstannane and azobis(isobutyronitrile) as a catalyst and distilling the product and the byproduct, bis(tributyltin) sulfide, in vacuo. Yields are 74-95% [798],... 

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