Catalytic formal carbyne transformation of phosphorus ylides Taiga Ando, Ryuhei Suzuki, Fritz Deufel, Kohsuke Ohmatsu, Takashi Ooi Nagoya University, Japan The cleavage of bonds corresponding to three valences on one carbon leads to the generation of carbyne, which has a dual radical and carbene reactivity. Its inherent ability to sequentially form three new covalent bonds in a single operation can provide a unique and versatile platform for the rapid construction of complex molecular architecture. However, the development of reactions of carbynes or carbyne equivalents has met with limited success due to the difficulty associated with generating and controlling the extremely reactive species. 1 Recently, carbyne equivalent generated from phosphorus ylide via photoredox-mediated C–H cleavage was proposed as a reactive intermediate in the development of reductive alkylation of phosphorus ylides with alkenes. 2 We envisioned that C–H functionalization of phosphorus ylide with preservation of C=P moiety could offer an opportunity for implementing consecutive polar reaction of the resulting functionalized phosphorus ylide, thereby enabling the unprecedented formal carbyne transformation. Specifically, single-electron oxidation of the nucleophilic ylides under visible-light photoredox conditions generates the corresponding electrophilic radical cations, which could engage in the addition to electron-rich alkenes to form alkylated ylides competent to undergo ensuing reaction with pertinent electrophiles, establishing a photocatalytic radical-polar crossover. Here, we disclose a three-component cycloaddition of phosphorus ylides with electron-rich alkenes and a,b-unsaturated carbonyls. This transformation allows for the rapid construction of the synthetically versatile functionalized six- membered carbocycles through the conversion of the C=P and the inert C–H bonds into the C=C and the C–C bonds. References 1. M. M. Wienk, R. A. J. Janssen, J. Am. Chem. Soc. 1997 , 119 , 5398. 2. (a) M. D. Vu, W.-L. Leng, H.-C. Hsu, X.-W. Liu, Asian J. Org. Chem. 2019 , 8 , 93. (b) M. Das, M. D. Vu, Q. Zhang, X.-W. Liu, Chem. Sci. 2019 , 10 , 1687.
P04F
© The Author(s), 2023
Made with FlippingBook Learn more on our blog