Wikipedia gives the following sequence of reactions for lithium burning, but unfortunately it does not mention how much energy it produces. This sequence is often classed as a fusion reaction, although the last step does involve fission. Many writers prefer to just call it lithium burning.
$$\begin{align}\\ \mathrm p+{}^6_3\mathrm{Li}&\longrightarrow{}^7_4\mathrm{Be}\ \text{(unstable)}\\ ^7_4\mathrm{Be}+\mathrm e^-&\longrightarrow{}^7_3\mathrm{Li}+\nu\\ \mathrm p+{}^7_3\mathrm{Li}&\longrightarrow{}^8_4\mathrm{Be}\ \text{(unstable)}\\ ^8_4\mathrm{Be}&\longrightarrow{}2\ ^4_4\mathrm{He}+\ \text{energy}\\ \end{align}$$
These reactions can occur at a lower temperature than the standard proton-proton chain, which is the dominant family of fusion reaction in stars less than 1.3 solar masses. (The CNO cycle is more important in larger stars).
Lithium burning is important in T Tauri pre-main sequence stars.
