New rhodium-catalyzed amination reactions†‡

Abstract

New transition metal-catalyzed reactions of norbornadiene with secondary amines are reported.

References

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7. General procedure: 89.3 mg [Rh(cod)₂]BF₄(0.22 mmol) and 115.4 mg PPh₃(0.44 mmol) were mixed in 10 ml THF. Subsequently, 0.38 ml morpholine (4.40 mmol) and 1.92 ml nbd (17.6 mmol) were added at room temp. The reaction was heated to reflux for 20 h before being cooled to room temp. After removal of the solvent in vacuo, the residue was dissolved in 20 ml CH₂Cl₂ and extracted three times with 5% HCl. NaOH was added to the combined aqueous phases until a pH of 9 was reached. The aqueous phase was then extracted three times with CH₂Cl₂. The combined organic layers were dried over MgSO₄ and the solvent was distilled off. The products were obtained after column chromatography (CHCl₃–MeOH = 30∶1). Isolated yields: 3a: 32%(252 mg); 3b: 40%(312 mg); 3c: 37%(266 mg); 3d: 34%(268 mg); 4c: 4%(23 mg).
8. We term this reaction of amines with norbornadiene a pseudo-1,3-addition in agreement with literature for 1,4-addition reactions.
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