Sulfur Atoms. Reactions of Gunning and Strausz

Their kinetic and product analysis is consistent with the working hypothesis indicated previously for insertions the singlet process is stereospecific, while the triplet process is at best only selective. Here, as in the reaction of sulfur atoms with alkenes, (217), some progress has been made in separating the problem of the reacting species and their reaction rates from the observed SS in the product (Gunning and Strausz, 1966). In general, however, interconversion rates of triplet cisoid and transoid diradicals are uncertain, and deductions from overall stereoselectivity are also uncertain. 

A study of the gas phase reactions of sulfur atoms with ethylene and propylene lias been recently carried out by Strausz and Gunning (98). Atomic sulfur, presumably in the (lD) metastable state, was generated by photolysis of carbonyl sulfide in the wavelength region 2550-2290 A., and the study was restricted to 25°C. Pure carbonyl sulfide yields carbon monoxide and sulfur as the main products. When ethylene and propylene are added, the carbon monoxide yield is decreased, tending to a value one half as large as in the absence of the olefins. Cyclic sulfides are simultaneously formed by addition of S atoms to the two olefins. The mechanism which accounts for the main features of the process is... 

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