Enantioselective conjugate addition of diethylzinc to enones catalyzed by a copper complex of chiral aryl diphosphite

Abstract

The 1,4-conjugate addition of diethylzinc to cyclohex-2-enone and cyclopent-2-enone catalyzed by a copper complex of a chiral aryl diphosphite gave the desired products with 90.2 and 76.6% ee respectively.

References

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10. Selected data for (S,S,S)-1 containing 0.5EtOH (solvent of crystallization): Calc. for C₆₀H₃₆O₆P₂·0.5C₂H₆O: C, 78.12; H, 4.16%. Found: C, 78.13; H, 4.16%; δ_P(CDCl₃) 145.7; δ_H(CDCl₃, 400MHz) 7.97 (d, J 8.8, 2H), 7.90 (d, J 8.0, 2H), 7.82 (dd, J₁ 8.0, J₂ 8.8, 4H), 7.73 (d, J 8.0, 2H), 7.52 (d, J 8.8, 2H), 7.37 (m, 8H), 7.16–7.31 (m, 14H), 6.53 (d, J 8.8, 2H), 3.72 (q, J 6.8, 1H), 2.36 (s, 0.5H), 1.24 (t, J 6.8, 1.5H); δ_C(CDCl₃) 147.2, 147.0, 146.5, 134.2, 132.7, 132.2, 131.4, 131.0, 130.8, 130.2, 130.0, 129.5, 128.3, 128.2, 128.1, 126.9, 126.8, 126.2, 126.0, 125.8, 125.1, 124.9, 124.6, 124.2, 122.4, 121.8, 121.7, 121.1; m/z(ESI) 915 (M⁺+ 1, 100%); Mp 196–198 °C (decomp.); [α]_D²⁰+346.6 (c 1.085, THF)[a rather different [α]_D²⁰ value was reported by Pringle et al.(ref. 11)].
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