  We study within the spin-boson dynamics the synchronization of quantum
tunneling with an external periodic driving signal. As a main result we find
that at a sufficiently large system-bath coupling strength (Kondo parameter
a>1) the thermal noise plays a constructive role in yielding both a frequency
and a phase synchronization in a symmetric two-level system. Such riveting
synchronization occurs when the driving frequency supersedes the zero
temperature tunneling rate. As an application evidencing the effect, we
consider a charge transfer dynamics in molecular complexes.
