Desulfurization Lithium-Ethylamine

Desulfonylation Lithium-Ammonia, 158 Lithium triethylborohydride, 168 Magnesium-Methanol, 170 Sodium dithionite, 281 Sodium naphthalenide, 294 Desulfurization Lithium aluminum hydride-Bis(cyclopentadienyl)nickel, 158 Lithium l-(dimethylamino)naph-thalenide, 165 Lithium-Ethylamine, 158 Dethioacetalization (see Hydrolysis of thioacetals and -ketals)... 

DESULFONYLATION Lithium-Ethylamine. Sodium-Ethanol. Sodium amalgam. Tetrakis(tnphenylphosphine)palladium. DESULFURATION ... 

In this synthesis the geometry of the acyclic double bonds is controlled through their formation as part of the thiane ring. Thiacyclohexanone (711) was converted to 4-thia-l-methylcyclohexene by reaction with methylmagnesium iodide and subsequent dehydration. Metallation of (712) with s-butyllithium and alkylation of the anion with the epoxide (713) gave a tertiary alcohol which was dehydrated to yield (714). A second alkylation of (714) with trails-4-chloro-3-methyl-2-butene 1-oxide (715) completed the carbon skeleton of the Cis juvenile hormone. Reduction of (716) with lithium in ethylamine and then desulfurization with Raney nickel led to trienol (717), a product converted previously to (718). 

Chiral allylic alcohols.1 Desulfuration of the (3-hydroxy sulfoxides 1 with Raney nickel (11, 292) proceeds with simultaneous reduction of the double bond, but can be effected selectively with lithium in ethylamine at - 78° to give optically active allylic alcohols (2). 

---