Abstract: This study reports an integrated tag-assisted continuous-flow liquid-phase peptide synthesis (CF-TAPS) platform based on a green solvent system, achieving a 3.7-fold reduction in process mass intensity (PMI) relative to the solid-phase peptide synthesis (SPPS) benchmark. The core innovation lies in a "dual-flow intensification" framework: first, a fixed-bed reactor was utilized for the efficient continuous-flow hydrogenation of the hydrophobic amino-tag carrier (BTPM), establishing the material foundation for end-to-end automation; second, a tunable binary solvent system (EA/DMSO) was synergized with a static-mixer-incorporated tubular reactor (SMTR) to ensure robust solvation and ultrafast reaction kinetics. This modular architecture integrated automated in-line membrane separation, transforming emulsion-prone washing into a high-throughput workflow and significantly compressing cycle times for coupling (52 s) and deprotection (38 s). The utility of this tag-based flow strategy was validated through the total synthesis of cell-penetrating peptide 5R , requiring only 1.05-1.2 mol of amino acids. Notably, the platform achieved a transformative 4-fold reduction in organic solvent consumption (OSC), providing a sustainable paradigm for green peptide manufacturing that effectively integrates the high atom economy of liquid-phase strategies with the automated industrial scalability of continuous processes.

Key words: Continuous-flow chemistry, Liquid-phase peptide synthesis (LPPS), Soluble tags, In-line membrane separation, Process mass intensity (PMI)