The Reaction of Amines with Benzyl Halides under CO2 Atmosphere

To find a useful, practical, and ecologically safer way to synthesize protected amines, the reactions of amines with benzyl halides under CO₂ atmosphere were systematically examined. For primary amines, the CO₂‐inserted products were obtained in higher yields in the presence of DBU as a base, under a high pressure of CO₂, and in a low‐polarity solvent (toluene/hexane 1 : 1). Secondary amines gave only low yields of CO₂‐inserted products.