Allylation of N-Heteroaryl Hydrazones

Significance

The asymmetric allylation of imines is an important method for the synthesis of chiral amines. Leighton and co-workers have made significant progress in this area with the development of a pseudoephedrine-derived allylation reagent (R. Berger, P. M. A. Rabbat, J. L. Leighton J. Am. Chem. Soc. 2003, 125, 9596). Limitations of the methodology include low enantioselectivity on reactions with aliphatic aldehyde-derived hydrazones, low reactivity with crotylation and cinnamylation reagents, and difficult removal of activating groups on the imine. In the present communication, the authors overcome many of these problems by the use of N-heteroaryl hydrazones.