  We calculate the orbital evolution of binary systems where the primary star
is an evolved red giant branch (RGB) star, while the secondary star is a
low-mass main sequence (MS) star or a brown dwarf. The evolution starts with a
tidal interaction causes the secondary to spiral-in. Than either a common
envelope (CE) is formed in a very short time, or alternatively the system
reaches synchronization and the spiraling-in process substantially slows down.
Some of the latter systems later enter a CE phase. We find that for a large
range of system parameters, binary systems reach stable synchronized orbits
before the onset of a CE phase. Such stable synchronized orbits allow the RGB
star to lose mass prior to the onset of the CE phase. Even after the secondary
enters the giant envelope, the rotational velocity is high enough to cause an
enhanced mass-loss rate. Our results imply that it is crucial to include the
pre-CE evolution when studying the outcome of the CE phase. We find that many
more systems survive the CE phase than would be the case if these preceding
spin-up and mass-loss phases had not been taken into account. Although we have
made the calculations for RGB stars, the results have implications for other
evolved stars that interact with close companions.
