This study presents a streamlined stereoselective synthesis strategy for constructing the highly congested cage-like tetracyclic core of cipadonoid A, employing visible-light photoredox catalysis to enable intramolecular Giese-type radical cyclization as a key step. Density Functional Theory (DFT) analysis revealed that the selective formation of the cis-fused AB bicyclic framework is controlled by intramolecular hydrogen bonding-mediated conformational stabilization. Notably, the synthesized B,D-seco-limonoid scaffold exhibited lysosomal biogenesis enhancing activity on par with its natural counterpart, with comparative bioassays demonstrating equivalent efficacy between the synthetic derivative and native cipadonoid A (1) in promoting lysosomal biogenesis.