The addition of cuprates to 1-aza-1,3-butadienes from BSMA and MSMA occurs under mild conditions and with satisfactory yields in the presence of BF3/Et2O. The regioselectivity of the addition is closely related to the nature of the transferable ligand in the organometallic reagent. The possibility of performing a sequential C4-Nu followed by a C3-E bond formation in a one-pot/two-steps 'tandem' reaction is discussed as well.