Iodonium Ylides as Carbene Precursors in Rh(III)-Catalyzed C–H Activation

Abstract

The rhodium­(III)-catalyzed coupling of C–H substrates with iodonium ylides has been realized for the efficient synthesis of diverse cyclic skeletons, where the iodonium ylides have been identified as efficient and outstanding carbene precursors. The reaction systems are applicable to both sp2 and sp3 C–H substrates under mild and redox-neutral conditions. The catalyst loading can be as low as 0.5 mol % in a gram-scale reaction. Representative products exhibit cytotoxicity toward human cancer cells at nanomolar levels.

Co(III), Rh(III) & Ir(III)‐Catalyzed Direct C−H Alkylation/Alkenylation/Arylation with Carbene Precursors

“…Herein, iodonium ylides utilized as a carbene precursors in Rh(III)‐catalyzed C−H functionalization's (Scheme 34). [48] …”

Enantioselective Synthesis of Fused Isocoumarins via Palladium-Catalyzed Annulation of Alkyne-Tethered Malononitriles

“…1 H NMR spectra were recorded at room temperature on a Bruker AVANCE NEO 400 MHz Digital NMR spectrometer and were reported relative to residual CDCl 3 (δ 7.26 ppm). 13 C NMR spectra were recorded on a Bruker AVANCE NEO 400 MHz Digital NMR spectrometer (100 MHz) and were reported relative to CDCl 3 (δ 77.16 ppm). Data for 1 H NMR were reported as follows: chemical shift (δ ppm) (multiplicity, coupling constant (Hz), integration).…”

“…Multiplicities were reported as follows: s = singlet, d = doublet, t = triplet, q = quartet, m = multiplet, br s = broad singlet. Data for 13 C NMR and 19 F NMR were reported in terms of chemical shifts (δ ppm). High-resolution mass spectra (HRMS) were obtained by use of a Bruker Compact TOF mass spectrometer in electrospray Unless otherwise noted, all chemicals were purchased.…”

“…1 H NMR (400 MHz, CDCl 3 ): δ 7.91 (dd, J = 7.9, 1.4 Hz, 1H), 7.56 (dd, J = 7.8, 1.4 Hz, 1H), 7.45 (td, J = 7.6, 1.5 Hz, 1H), 7.35 (td, J = 7.7, 1.4 Hz, 1H), 3.93 (s, 3H), 3.35 (t, J = 7.4 Hz, 2H), 3.08 (t, J = 7.4 Hz, 2H). 13 Synthesis of Methyl 2-(5,5-Dicyanopent-1-yn-1-yl)benzoate (S3). To a stirred solution of NaH (1.60 g, 40.0 mmol, 4.0 equiv, 60%, dispersion in paraffin liquid) in THF (140 mL) was added malononitrile (2.65 g, 40.0 mmol, 4.0 equiv) at 0 °C.…”

Selenonium ylides: synthesis, characterization, and applications to photo-induced cyclopropanation reactions

“…In 2007, Jenks et al developed C,S-sulfonium ylides based on the thiophene moiety as a useful precursor for carbenes using a photochemical activation methodology (Scheme 1a) [9]. The synthesized sulfonium ylides were stable, easy to handle, and could generate free carbenes using ultraviolet (UV) irradiation without a catalyst [10,15,17]. These studies reported that onium ylides with relatively large conjugated systems could photochemically generate the corresponding carbene species.…”