Development of strong Brønsted base catalysis: catalytic direct-type Mannich reactions of non-activated esters via a product-base mechanism.

A catalytic Mannich reaction of a simple ester with no activating functionality at the α-position via a product-base mechanism was reported. The desired Mannich adducts were obtained in high yields using a catalytic amount of KH. This is a rare example of a Brønsted base-catalyzed Mannich reaction of unactivated esters as substrates.