Halides, sulfonyl, addition alkenes

The free radical additions of sulfonyl halides to alkenes, catalyzed by light or typical chemical radical initiators (In), were first investigated in the 1950s69. The products which are / -halo sulfones (22) were obtained via a chain reaction in which RSO j acts as the chain carrier, namely61-62,70,71... 

The Smiles rearrangement 5-28 Addition of ArSSCl to alkenes 9-35 Oxidation of thiols 9-54 Reduction of sulfonyl halides... 

Sulfenyl halides (1) will also undergo nucleophilic addition with alkenes (Scheme 1) to yield the episulfides (7), which can suffer a further nucleophilic addition to give the sulfides (8). The nucleophilic substitutions of sulfenyl (1) (see Chapter 4, p. 54) and sulfonyl (3) chlorides (see Chapter 7, p. 106) probably generally proceed by the SN2 reaction mechanism, which with the sulfonyl halide (3) involves the trigonal bipyramidal transition... 

Several thiols occur naturally for example, skunk secretion contains 3-methyll-butanethiol and cut onions evolve 1-propanethiol, and the thiol group of the natural amino acid cysteine plays a vital role in the biochemistry of proteins and enzymes (see Introduction, p. 2). Primary and secondary thiols may be prepared from alkyl halides (RX) by reaction with excess sodium thiolate (SN2 nucleophilic substitution by HST) or via the Grignard reagent and reaction with sulfur. Tertiary thiols can be obtained in good yields by addition of hydrogen sulfide to a suitable alkene. Thiols can also be prepared by reduction of sulfonyl chlorides (Scheme l).la,2a... 

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