Search for the semi-leptonic decays ${\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{\pi }^{+}{\pi }^{-}{e}^{+}{\nu }_e$ and ${\mathrm{\Lambda }}_c^{+}\to p{K}_S^0{\pi }^{-}{e}^{+}{\nu }_e$

We search for the semi-leptonic decays ${\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{\pi }^{+}{\pi }^{-}{e}^{+}{\nu }_e$ and ${\mathrm{\Lambda }}_c^{+}\to p{K}_S^0{\pi }^{-}{e}^{+}{\nu }_e$ in a sample of 4.5 ${\mathrm{f}\mathrm{b}}^{-1}$ of $e^{+}{e}^{-}$ annihilation data collected in the center-of-mass energy region between 4.600 GeV and 4.699 GeV by the BESIII detector at the BEPCII. No significant signals are observed, and the upper limits on the decay branching fractions are set to be $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to \mathrm{\Lambda }{\pi }^{+}{\pi }^{-}{e}^{+}{\nu }_e)<3.9\times {10}^{-4}$ and $\mathcal{B}({\mathrm{\Lambda }}_c^{+}\to p{K}_S^0{\pi }^{-}{e}^{+}{\nu }_e)<3.3\times {10}^{-4}$ at the 90% confidence level, respectively.