A Highly Efficient Chiral Amine-Thiourea Catalyst

Significance

The Mannich reaction of fluorinated keto esters 1 and N-Boc imines 2, catalyzed by ­bifunctional thiourea catalyst 3 is reported. The combination of the naturally occurring amino acid tryptophan as the chiral scaffold and a thiourea moiety as hydrogen-bond donor led to a highly selective bifunctional catalyst 3. Not only fluorinated keto esters, such as 1, but also non-fluorinated analogues and malonates could be used in the ­reaction to give the desired products in high yields and enantioselectivites.

Review: A. G. Doyle, E. N. Jacobsen Chem. Rev. 2007, 107, 5713-5743.