  Exclusive semileptonic B meson decays to orbitally excited D mesons are
investigated in the infinitely heavy quark limit in the framework of the
relativistic quark model based on the quasipotential approach. The B\to
D^{**}e\nu Isgur-Wise functions \tau_{3/2}(w) and \tau_{1/2}(w) are determined.
It is found that the relativistic transformation of the meson wave functions
(Wigner rotation of the light quark spin) contribute already at the leading
order of the heavy quark expansion.
