Pd‐Catalyzed Synthesis of α‐Aryl Vinylphosphonates via Suzuki Arylation of α‐Phosphonovinyl Nonaflates

Abstract

The first palladium-catalyzed method for the arylation of α-phosphonovinyl nonaflates is described. Using a catalyst comprised of Pd(OAc) 2 and SPhos, terminal and internal α-aryl vinylphosphonates could be efficiently accessed under mild conditions. The reaction features a broad coupling partner scope and tolerates many functional groups.

α‐Phosphonovinyl Arylsulfonates: An Attractive Partner for the Synthesis of α‐Substituted Vinylphosphonates through Palladium‐Catalyzed Suzuki Reactions

“…Diethyl [1‐(Benzo[ d ][1,3]dioxol‐5‐yl)vinyl]phosphonate (10k): 26c Pale yellow oil, 83.5 mg, 98 % yield. 1 H NMR (500 MHz, CDCl 3 ): δ = 1.30 (t, J = 7.1 Hz, 6 H), 4.04–4.17 (m, 4 H), 5.97 (s, 2 H), 6.08 (dd, J 1 = 1.4, J 2 = 45.6 Hz, 1 H), 6.25 (dd, J 1 = 1.4, J 2 = 21.7 Hz, 1 H), 6.79 (dd, J 1 = 0.5, J 2 = 8.5 Hz, 1 H), 7.03–7.05 (m, 2 H) ppm.…”

“…Diethyl [1‐(4‐Vinylphenyl)vinyl]phosphonate (10m): 26c Pale yellow oil, 79.0 mg, 99 % yield. 1 H NMR (500 MHz, CDCl 3 ): δ = 1.28 (t, J = 7.1 Hz, 6 H), 4.03–4.17 (m, 4 H), 5.27 (d, J = 10.9 Hz, 1 H), 5.77 (d, J = 17.6 Hz, 1 H), 6.17 (dd, J 1 = 1.4, J 2 = 45.7 Hz, 1 H), 6.32 (dd, J 1 = 1.4, J 2 = 22.0 Hz, 1 H), 6.71 (dd, J 1 = 10.9, J 2 = 17.6 Hz, 1 H), 7.39 (d, J = 8.1 Hz, 2 H), 7.50 (d, J = 8.2 Hz, 2 H) ppm.…”

“…Diethyl [1‐(Benzo[ b ]thiophen‐2‐yl)vinyl]phosphonate (18c): 26c Pale yellow oil, 72.8 mg, 82 % yield. 1 H NMR (500 MHz, CDCl 3 ): δ = 1.33 (t, J = 7.1 Hz, 6 H), 4.08–4.23 (m, 4 H), 6.30 (d, J = 6.8 Hz, 1 H), 6.36 (d, J = 15.5 Hz, 1 H), 7.30–7.36 (m, 2 H), 7.64 (s, 1 H), 7.73–7.78 (m, 2 H) ppm.…”

“…Recently, as a part of our continuing interest in transition‐metal‐catalyzed cross‐coupling reactions,24,25 we conducted on the synthesis of terminal vinylphosphonates under palladium‐catalyzed Suzuki–Miyaura cross‐coupling reaction conditions 26. With α‐(pseudo)halovinylphosphonates as the electrophilic coupling partner,26a,26c a range of α‐aryl vinylphosphonates were efficiently prepared under palladium‐catalyzed Suzuki reaction conditions. From the viewpoint of step and atom economy, O ‐based electrophiles are more attractive than α‐halovinylphosphonates,27 which require at least four steps from starting materials (Scheme ).…”

“…From the viewpoint of step and atom economy, O ‐based electrophiles are more attractive than α‐halovinylphosphonates,27 which require at least four steps from starting materials (Scheme ). Relative to nonaflates (Nf),26c,28 corresponding enol‐derived arylsulfonates have advantages in handling, economy, and stability. In this paper, we report the synthesis of various α‐phosphonovinyl arylsulfonates and describe an overview of the palladium‐catalyzed Suzuki–Miyaura cross‐coupling reactions of α‐phosphonovinyl arylsulfonates with aryl, heteroaryl, and alkylboron reagents.…”