Mukaiyama reagent-promoted metal-free preparation of alkynyl sulfones and phosphonates under mild conditions

Direct and Efficient Synthesis of Sulfonium Acyl Sulfonylmethylide Ylides from Acetylenic Sulfones and Dimethyl Sulfoxide

“…3, 143.0, 142.5, 142.1, 141.3, 130.3, 129.6, 129.3, 129.1, 128.5, 127.8, 127.3, 126.3, (82.6) 80.9, 31.0 (26.9), 21.4. Both the ketonic and enolic zwitterionic forms are observed in its 13 C NMR spectrum for this product (data for the ketonic form are in parentheses). The enolic zwitterionic form is the major form in its solution.…”

“…Various acetylenic sulfones 1 were prepared from the corresponding arylacetylenes and sodium sulfinates in the presence of iodine and tert-butyl hydroperoxide 12 or from βketosulfone by treatment with 2-chloro-1-methylpyridin-1-ium iodide (CMPI) and Et3N. 13 Initially, acetlenic sulfone 1-methyl-4-((phenylethynyl)sulfonyl)benzene ( 1a) was employed as a model substrate to react with DMSO to optimize reaction conditions. We first screened the solvents, including nitrobenzene, mesitylene, N,N,N'N',N",N"hexamethylphosphoric triamide (HMPA), N,Ndimethylacetamide (DMA), and dimethyl sulfoxide (DMSO), at 160 o C (Table 1, entries 15).…”

“…[8c,11b] For our products 2, some broadened signals were observed in both 1 H and 13 C NMR spectra in most cases, for example, the ortho hydrogen(s) of the acetylenic and/or sulfonyl aryl group(s), and some dimethyl group on the sulfur atom in 1 H NMR spectra; three carbon signals for the C(O)C-SMe2 moiety in 13 C NMR spectra, revealing that the synthesized ylides 2 exist in different resonance forms (Figure 1). Importantly, both its ketonic form I (183.6 ppm for C=O, 82.6 ppm for C=S, and 26.9 ppm for SMe2) and enolic form III (181.3 ppm and 80.9 ppm for -OC=C, 31.0 ppm for SMe2) were observed for ylide 2f in its 13 C NMR spectrum. For all aroylmethylides, their carbonyl carbon atoms appeared at 181.5187.3 ppm, more close to that of the ketonic form I of 2f, while the carbonyl carbon atoms of alkanoylmethylides were observed at 191.0192.0 ppm.…”

“…After concentration under reduced pressure the residue was purified by column chromatography with petroleum ether (60-90 °C fraction) and EtOAc (10:1, v/v) as eluent to afford the corresponding sulfone 1. Method B: 13 for the synthesis of 1d, 1g, 1l, 1m, and 1p β-Ketosulfone (1.0 equiv, prepared by referring literature 14 ), 2-chloro-1methylpyridin-1-ium iodide (CMPI) (1.2 equiv. ), and Et3N (5.0 equiv.)…”

Synthesis of Alkynyl Sulfones

“…Finally, during this year, Dong and An reported an interesting variation of the dehydration of β‐arylsulfonylketones reported by Craig and Clasby in 1992. Dong's methodology has the advantage of being performed in a single step, using 2‐chloro‐1‐methylpyridinium iodide (CMPI), better known as the “Mukaiyama reagent”, as a dehydrating agent . A more complete study of the reaction scope was conducted by the authors for up to 21 alkynyl sulfone derivatives, which include diverse substituents on both the alkyne and sulfone moieties, were synthesized.…”