Transition Metal Complexes in Organic Synthesis, Part 72: [1] Iron-Mediated Diastereoselective Spiroannelation of Dimethyl Aminomalonate to the 2-Azaspiro[4.5]decane Ring System

Abstract

The iron-mediated diastereoselective spiroannelation of dimethyl aminomalonate opens up a highly efficient route to the 2-azaspiro[4.5]decane ring system.

Key words

cyclizations - Diels-Alder reactions - diene complexes - iron - spiro compounds

References

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11

Compound 7: yellow crystals, mp 75 °C. Anal. Calcd for C₂₄H₂₂FeN₂O₁₁: C, 50.55; H, 3.89; N, 4.91; found: C, 50.39; H, 4.18; N, 4.86.

12

Crystal data for 7: C₂₄H₂₂FeN₂O₁₁, M = 570.29, orthorhombic, space group Pccn (no. 56), a = 35.927 (8), b = 11.434 (2), c = 14.182 (2) Å, U = 5826 (2) ų, Z = 8, D _c = 1.300 g cm^-3, µ = 0.574 mm^-1, T = 293 (2) K, λ = 0.71069 Å, 5112 reflections measured, 5112 independent, 343 parameters. The structure was solved by direct methods and refined by full-matrix least squares on F ². R ₁ [I>2σ(I)] = 0.0547, wR ₂ = 0.1807. Details of the crystal structure investigation have been deposited at the Cambridge Crystallographic Data Centre (CCDC 233245).

15

Crystal data for anti-11: C₂₂H₂₄N₄O₇, M = 456.45, orthorhombic, space group Pbca (no. 61), a = 10.473 (8), b = 9.000 (5), c = 45.59 (2) Å, U = 4298 (4) ų, Z = 8, D _c = 1.411 g cm^-3, µ = 0.107 mm^-1, T = 293 (2) K, λ = 0.71069 Å, 3318 reflections measured, 2810 independent (R _int = 0.0369), 298 parameters. The structure was solved by direct methods and refined by full-matrix least squares on F ². R ₁ [I>2σ(I)] = 0.0700, wR ₂ = 0.1510. Details of the crystal structure investigation have been deposited at the Cambridge Crystallographic Data Centre (CCDC 233244).