Sulfur-type reducing agents

Treatment of Fischer-type carbene complexes with different oxidants can lead to the formation of carbonyl compounds [150,253]. Treatment with sulfur leads to the formation of complexed thiocarbonyl compounds [141]. Conversion of the carbene carbon atom into a methylene or acetal group can be achieved by treatment with reducing agents. Treatment of vinylcarbene complexes with diborane can also lead to demetallation and formation of diols [278]. The conversion of heteroatom-substituted carbene complexes to non-heteroatom-substituted carbene complexes... 

Zinc dust (Zn) is not a compound but a gray powder that is used as a pigment and acts as an excellent reducing agent and catalyst. It is dangerous because it can explode when exposed to moist air and may heat up and ignite spontaneously. When mixed with dry, powdered sulfur, it makes an excellent dry propellant-type rocket fuel, but is dangerous to handle. 

Leuco Sulfur Dyes (C.I. Leuco Sulphur). These liquid dyes already contain the reducing agent required for dyeing. They must simply be diluted with water before application. Ecologically more favorable, low-sulfide types have come onto the market recently. 

Aromatic sulfonyl chlorides can be converted into thiophenols by many types of reducing agent, but most simply by zinc dust in hydrochloric or sulfuric acid, yields being mostly very good.522 Preparatively the most rewarding process is their reduction in boiling glacial acetic acid by red phosphorus in the presence of catalytic amounts of iodine.523... 

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