$B^{+}\to D_s^{*+}\gamma$ and $B^{+}\to D^{*+}\gamma$ as probes of $V_{\mathrm{ub}}$

The decays $B^{+}\to D_s^{*+}\gamma$ and $B^{+}\to D^{*+}\gamma$ can be used for an extraction of $|V_{\mathrm{ub}}|.$ When the b and c quarks are nearly degenerate, the rate for these modes can be determined in terms of other observed rates, namely $B\overline{B}$ mixing and $D^{*}\to D\gamma$ decay. To this end, we introduce a novel application of heavy quark and flavor symmetries. Although somewhat unrealistic, this limit provides us with a first estimate of these rates.