A multi-step method for the continuous synthesis of ibuprofen or a synthetic precursor of ibuprofen is provided that does not require any intermediate purification or isolation steps and uses reagents compatible with downstream reactions. According to some embodiments, a method is provided wherein isobutylbenzene and a propionyl compound may be converted into a first product in a first Friedel Crafts acylation reaction. The first product may then be converted into a second product in a 1,2-aryl migration reaction. Finally, the second product may be converted into ibuprofen in a hydrolysis reaction. The present invention also provides a method wherein only the first and second reaction steps or only the second and third reaction steps are performed. An apparatus is also provided having two or more microreactors and two or more junctions in particular arrangements for the synthesis of ibuprofen or a synthetic precursor of ibuprofen.