Sulfenyl reagents

A new stable sulfenylating reagent 3-phenylsulfenyl-2-GV-cyano-imino)thiazolidine 57 has been described. It reacts with amines or thiols to give sulfenamides or disulfides in excellent yields. a-Sulfenylation of carbonyl compounds also proceeds smoothly and if an optically active 4-diphenylmethyl substituent is attached to the thiazolidine ring (58), the cyclic (3-ketoester 59 can be sulfenylated in high yield with an ee of 96% to give the sulfide 60 <00SL32>. 

Protected sulfenylation reagents (Lg-S-Pg) a-sulfenylate aldehydes, using steri- cally encumbered chiral pyrrolidines as enantioselective organocatalysts.298... 

Thiosulfonic S-esters3 are powerful sulfenylating reagents,4 more reactive than the commonly used disulfides, and more stable than the very reactive sulfenyl halides. In addition, they have found wide industrial applications as biologically active compounds or in polymer production.3 Their use, however, has been limited by the lack of easy and practical preparations. 

Similar results have been observed for other sulfenylating reagents. The somewhat more electrophilic trifluoroethylsulfenyl group shows a shift toward Markovnikov regioselectivity but retains anti stereospecificity, indicating a bridged intermediate. ... 

General Discussion. (V-Phenylthiophthalimide has been shown to be a mUd sulfenylating reagent that is useful for a range of synthetic appUcations. This reagent reacts with amines and thiols to give the corresponding sulfenyl amines and disulfides respectively (eq 1). 

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