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Lewis Acid-Activated 8-Quinolinethiosulfonates: An Efficient Methodology for CS(alkyl) Bond Formation

preprint
submitted on 17.07.2020 and posted on 20.07.2020 by erwan galardon
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

History

Email Address of Submitting Author

erwan.galardon@parisdescartes.fr

Institution

UMR8601 - Université de Paris

Country

France

ORCID For Submitting Author

0000-0002-4371-6119

Declaration of Conflict of Interest

none

Version Notes

first submitted

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