Comprehensive SummaryA total synthesis of 17‐membered macrocyclolipopeptide dysoxylactam A, a potent agent reversing P‐glycoprotein (P‐gp)‐mediated multidrug resistance (MDR) in cancer cells, was developed from the starting material (S)‐2‐methylbutanal in a linear sequence of 12 steps with 23.2% overall yield. The key steps include proline‐catalyzed asymmetric aldol reaction, Evans aldol reaction and Krische allylation to construct the multiple stereocenters containing fragment, and ring‐closing metathesis to furnish the macrocycle. This total synthesis facilitates the preparation of large amount samples of dysoxylactam A and the side chain simplified derivatives for further biological tests and preliminary structure‐activity relationship exploration.