Toward identifying optimal conditions for inducing the addition of pentadienyl anions to imines to furnish the branched adducts,
a brief exploratory study was undertaken.
In the event, 1,4-pentadiene (8) was deprotonated by treatment with n-BuLi at 78 C, and transmetalation of the lithio anion 9 thus produced with other metal halide salts gave the anions 10aec (Scheme 2).