Graphical Abstract To create your abstract, type over the instructions in the template box below. Fonts or abstract dimensions should not be changed or altered. Stereoselective synthesis of N,N-acetals by cyclization of an N-acyliminium ion through interaction with an N-sulfonyl group Shinji Yamada * and Yasuko Takahashi Department of Chemistry, Ochanomizu University, Bunkyo-ku, Tokyo112-8610, Japan Leave this area blank for abstract info.