The invention discloses a novel synthesis process of 
prasugrel. The novel synthesis process comprises the steps: firstly, carrying out benzyl protection by taking 4, 5, 6, 7-tetrahydrothieno[3, 2-c]
pyridine, 
benzaldehyde and 
sodium triacetoxyborohydride as starting raw materials to generate 5-benzyl-4, 5, 6, 7-tetrahydrothieno[3, 2-c]
pyridine; then, brominating the 5-benzyl-4, 5, 6, 7-tetrahydrothieno[3, 2-c]
pyridine by using 
hydrobromic acid to obtain 2-bromo-5-benzyl-4, 5, 6, 7-tetrahydrothieno[3, 2-c]pyridine; next, catalytically synthesizing 2-acetoxy-5-benzyl-4, 5, 6, 7-tetrahydrothieno[3, 2-c]pyridine by taking 
palladium acetate as a catalyst and XPhos as a ligand; and finally, carrying out hydrodebenzylation, and 
coupling the product with alpha-bromo-o-fluorobenzyl cyclopropyl 
ketone to obtain a target molecule 2-acetoxy-5-(alpha-cyclopropylcarbonyl-2-fluorobenzyl)-4, 5, 6, 7-tetrahydrothieno[3, 2-c]
pyridine hydrochloride, i.e., the 
prasugrel hydrochloride. The process is simple, convenient and novel in 
route, easy to obtain raw materials, mild in condition, convenient to operate, high in total yield up to 80-90% and suitable for large-scale production.