This paper is dedicated to Professor Masahiro Murakami for his inspiring contributions
to chemical science.
Abstract
Described here is an efficient method for the modular synthesis of 2-sulfonylthiazole
derivatives via heteroaryl C–H sulfonylation. The protocol is composed of two stages
involving O-activation of thiazole N-oxides and nucleophilic addition of a sulfinate, which induces N(3)-deoxygenation
and C(2)-sulfonylation. The vicarious substitution is performed most effectively by
using 4-methoxybenzoyl chloride for O-acylation while employing sodium [tert-butyl(dimethyl)silyloxy]methanesulfinate (TBSOMS-Na) as the nucleophile. The sulfones
thus obtained can be converted to an array of thiazolyl sulfones, sulfonamides, and
sulfonyl fluorides by displacing the silyloxymethyl moiety with alkyl, aryl, amino,
and fluoro groups. The C–H sulfonylation approach, in combination with a sulfoxylate
(SO2
2–) strategy, provides direct access to sulfonylated thiazole scaffolds without recourse
to the use of 2-halothiazoles.
Key words
silyloxymethanesulfinate - C–H functionalization - modular synthesis - azole
N-oxides - sulfonylazoles