  In the neutral B meson system, it is possible to measure the CKM angle alpha
using the decay mode b -> u ubar d in the presence of pollution from gluonic b
-> d penguin decays. Here the recent status of the measurements of CP-violating
asymmetry parameters using time-dependent analyses in
  B -> pi+pi- and B -> rho pi decays and the perspectives of a sin2alpha
measurement are presented.
