A simple method for α‐position deuterated carbonyl compounds with pyrrolidine as catalyst

A simple, cost‐effective method for deuteration of carbonyl compounds employing pyrrolidine as catalyst and D 2 O as deuterium source was described. High degree of deuterium incorporation (up to 99%) and extensive functional group tolerance were achieved. It is the first time that secondary amines are used as catalysts for H/D exchange of carbonyl compounds, which also allow the deuteration of complex pharmaceutically interesting substrates. A possible catalytic mechanism, based on the hydrolysis of 1‐pyrrolidino‐1‐cyclohexene, for this pyrrolidine‐catalyzed H/D exchange reaction has been proposed.