A palladium-catalyzed three-component reaction between 5-(2-chloroquinolin-3-yl) oxazoles, isocyanides, and water to yield 3-(oxazol-5-yl)quinoline-2-carboxamides is described. Interestingly, sulfonylation occurred when the same reaction was performed with toluenesulfonylmethyl isocyanide (TosMIC) as an isocyanide source. The reaction with 5-(2-chloroquinolin-3-yl)oxazoles and TosMIC in the presence of Cs
2
CO
3
in DMSO afforded 5-(2-Tosylquinolin-3-yl)oxazoles. In basic media, TosMIC probably decomposed to generate Ts
−
species, which were replaced with Cl
−
. Tandem oxazole formation with subsequent sulfonylation of 2-chloroquinoline-3-carbaldehydes to form directly 5-(2-tosylquinolin-3-yl)oxazoles was also investigated.
A highly selective synthesis of (Z)-1-bromo-1-sulfonyl alkenes via Cs2CO3-promoted sulfonylation of 1,1-dibromo-1-alkenes with sodium sulfinates is described. Notably, using excess amounts of Cs2CO3 and sodium sulfinate in such a reaction regenerated the parent aldehyde. Interestingly, the reaction of 1-(2,2-dibromovinyl)-2-nitrobenzene in the presence of sulfinates and Cs2CO3 produced isatin. The Sonogashira cross coupling of synthesized (Z)-1-bromo-1-sulfonyl alkenes with phenylacetylene gave selectively the corresponding sulfonylalkynyl alkenes.
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