Not only the reaction rate but also the regioselectivity in the scandium bis(perfluorooctanesulfonyl)amide-catalyzed Baeyer-Villiger reaction is remarkably increased by the development of the fluorous nanoflow microreactor system continuously controlled by the nanofeeder DiNaS (Direct Nanoflow System) even in the lowest concentration of the catalyst (<< 0.1 mol%). The Baeyer-Villiger reaction completes within few seconds as a contact time in the nanoflow microreactor to give the lactone products with high regioselectivity without hydrolysis. (C) 2006 Elsevier B.V. All rights reserved.