The importance of sulfur-containing compounds in various fields, ranging from material
science1-2 to medicinal chemistry, 3
has called for the development of synthetic strategies to
form carbon-sulfur (C-S) bonds. Thus, numerous approaches based on the nucleophilicity of
thiols have been designed over the years, which mostly use air-sensitive noble metal catalysts.4-
9
At the opposite, the use of electrophilic sulfur reagents is also a powerful, more eco-friendly
approach, in particular for the sulfenylation of C-H bonds into C-S bonds.10-11 In this context,
the sulfenylation of indoles (Equation 1) has become a benchmark reaction to develop and test
new sulfenyl transfer reagents, because indoles are good nucleophiles and their occurrence in
many natural products or biological active compounds makes them attractive synthetic
targets.12-14 For instance, metal-catalyzed or metal-free protocols have been proposed, in
which disulfides, sulfinic acid and their salts, sulfonyl chlorides, sulfonylhydrazine, or Nthiophtalimides are used as source of electrophilic sulfur.10,15-16 Thiosulfonates (RSO2SR’) are
another class of emerging17 reagents, which were also studied for C-S bond formation18-20 and
for indole sulfenylation.21 However, despite the large pool of sulfenylation agents listed above,
the difficult activation of the chalcogen centre essentially limits these reagents to the formation
of C-S(aryl) bonds. On the other hand, the transfer of alkylsulfenyl groups requires harsher
activating conditions and is so far still limited<br>
Lewis Acid-Activated 8-Quinolinethiosulfonates: An Efficient Methodology for CS(alkyl) Bond Formation
