Regioselective 1,2-insertion of Ru into the C–S bond in 3-substituted thiophenes

Abstract

Reactions of [Ru(cod)(cot)] 1 [cod = cycloocta-1,5-diene, cot = cycloocta-1,3,5-triene] with 3-acetyl(or formyl)thiophene and 2-acetyl(or formyl) thiophene in the presence of depe [1,2-bis(diethylphosphino)ethane] lead to completely regioselective 1,2- or 1,5-insertion into the C–S bond giving the new thiaruthenacycles [Ru(SCR[double bond, length half m-dash]CHCR′[double bond, length half m-dash]CH)(depe)₂] [R = H, R′ = COMe (2a); R = H, R′ = CHO (2b); R = COMe, R′ = H (3a); R = CHO,R′ = H (3b)], respectively.

References

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5. As a typical example, spectroscopic and analytical data of 2a: Found: C, 48.33; H, 8.64; S, 5.09. Calc. for C₂₆H₅₄OP₄RuS: C, 48.81; H, 8.51; S, 5.01%. ¹H NMR (300 MHz, CD₃OD): δ 10.73 (br d, ³J_HP 18.0 Hz, 1 H, H¹), 6.61 (dd, ³J_HH 10.0, ⁴J_HH 1.8 Hz, 1H, H₃), 5.90 (t, ³J_HH 10.0, ⁴J_HP 10.0 Hz, 1H, H⁴), 2.25 (s, 3H, COCH₃), 2.2–0.8 (m, 48H, 2 depe). ³¹P{¹H} NMR (121 MHz, CD₃OD), AMNX spin system: δ 54.8 (td, J 20.0, 16.0 Hz, 1P, eq-P trans to S), 48.5 (dt, J329.4, 20.0 Hz, 1P, ap-P), 45.5 (ddd, J 329.4, 22.0, 17.0 Hz, 1P, ap-P), 28.8 (dt, J 20.0, 16.0 Hz, 1P, eq-P trans to C). Selected ¹³C{¹H} NMR (75.5 MHz, CD₃OD): δ 200.8 (dtd, ²J_CP 57.3, 15.0, 8.0 Hz, C¹), 196.1 (d, ³J_CP 8.3 Hz, C⁴). IR(KBr, cm ^–1): 1615 (ν_C=O).
6. Crystal data: for C₂₆H₅₂OP₄RuS 2b: M= 625.71, monoclinic, space group P2₁/n(no. 14), a= 10.638(5), b= 15.753(5), c= 18.502(4)Å, β= 99.22(2)°, V= 3060(1)ų, T= 293 K, Z= 4, µ(Mo-Kα)= 8.06 cm ^–1, R(R_w)= 0.043(0.045) for 3792 reflections. For C₅₁H₇₇OP₄RuSB 5a: M= 974.0, monoclinic, space group P2₁/_c(no. 14), a= 11.485(5), b= 24.678(5),c= 18.369(4)Å, β= 95.22(3)°,V= 5184(2)Å 3 , T= 293 K, Z= 4, µ(Mo-Kα)= 5.00 cm ^–1, R(R_w)= 0.068(0.081) for 6755 reflections. Single crystals of both 2b and 5a were recrystallised from acetone and mounted in a glass capillary. Both structures were solved using heavy atom Patterson methods and refined by full-matrix least squares on F. CCDC 182/1364. See http://www.rsc.org/suppdata/cc/1999/1793/ for crystallographic data in .cif format.
7. As a typical example, spectroscopic and analytical data of 3a: Found: C, 48.10; H, 9.24; S, 4.85. Calc. for C₂₆H₅₄OP₄RuS: C, 48.81; H, 8.51; S, 5.01%. ¹H NMR (300 MHz, C₆D₆): δ 8.36 (ddq ³J_HP 18.0, 3.0, ³J_HH 12.0 Hz, 1H, H¹), 7.98 (d, ³J_HH 7 Hz, 1H, H³), 7.39 (tdt, ⁴J_HP 12.3, 3.0, ³J_HH 7.5 Hz, 1H, H₂), 2.86 (s, 3H, COCH₃), 2.5–0.5 (m, 48H, 2depe). ³¹P{¹H} NMR (121 MHz, C₆D₆), AMNX spin system: δ 53.6 (td, J 20.7, 13.8 Hz, 1P, eq-trans to S), 46.7 (dt, J371.4, 21.0 Hz, 1P, ap-P), 43.3 (ddd, J371.4, 19.1, 15.2 Hz, 1P, ap-P), 30.3 (dt, J17.0, 15.0 Hz, 1P, eq-P trans to C). Selected ¹³C {¹H} NMR (75.5 MHz, C₆D₆): δ 199.2 (d, ³J_CP 7.5 Hz, C⁴), 169.6 (dtd, ²J_CP 57.3, 16.8, 9.8 Hz, C¹). IR(KBr, cm ^–1): 1636 (v_C=O).
8. T. Morikita, M. Hirano, A. Sasaki and S. Komiya, Inorg. Chim. Acta, 1999, 291, 341.
9. Thiophenes investigated: 2-methyl-, 3-methyl- and 2,5-dimethyl-thiophene.
10. As a typical example, selected spectroscopic and analytical data of 5a: Found: C, 62.52; H, 8.00; S, 3.85. Calc. for C₅₁H₇₇BOP₄RuS: C, 62.89; H, 7.97; S, 3.29%. ¹H NMR (300 MHz, acetone-d₆): δ 9.78 (ddq, ³J_HP= 16.0, 4.6, ³J_HH 12.0 Hz, 1H, H¹), 7.88 (d, ³J_HH 7.8 Hz, 1H, H³), 7.00–6.90 (m, 1H, H²), 2.45 (d, J2.4 Hz, 3H, SCH₃), 2.37 (s, 3H, COCH₃). ³¹P{¹H} NMR (121 MHz, acetone-d₆), AMNX spin system: δ 54.5 (ddd, J29.0, 19.4, 16.5 Hz, 1P, eq-P trans to S), 48.1 (dt, J244.3, 19.4 Hz, 1P, ap-P), 44.3 (ddd, J244.3, 29.0, 14.6 Hz, 1P, ap-P), 29.5 (ddd, J19.4, 17.0, 14.6 Hz, 1P, eq-P trans to C). IR(KBr, cm^–1): 1643 (v_C=O). Molar electric conductivity in acetone: Λ= 7.99 S cm ² mol ^–1.
11. (a) S. Harris and R. R. Chianelli, J. Catal., 1984, 86, 400; (b) L. Dong, S. B. Duckett, K. F. Ohman and W. D. Jones, J. Am. Chem. Soc., 1992, 114, 151.
12. Preliminary semiempirical calculations were carried out on 3-acetyl- and 3-formyl-thiophene using the MOPAC program in the Cache calculation package. Coefficients for C² and C⁵ were –0.62 and –0.40 for 3-acetyl thiophene and –0.63 and –0.41 for 3-formyl thiophene, respectively.