Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations

Koichi Mitsudo; Junya Yamamoto; Tomoya Akagi; Atsuhiro Yamashita; Masahiro Haisa; Kazuki Yoshioka; Hiroki Mandai; Koji Ueoka; Christian Hempel; Jun-Ichi Yoshida; Seiji Suga

doi:10.3762/bjoc.14.100

Stereoselective nucleophilic addition reactions to cyclic N-acyliminium ions using the indirect cation pool method: Elucidation of stereoselectivity by spectroscopic conformational analysis and DFT calculations

Beilstein J Org Chem. 2018 May 24:14:1192-1202. doi: 10.3762/bjoc.14.100. eCollection 2018.

Affiliations

¹ Division of Applied Chemistry, Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka, Kita-ku, Okayama 700-8530, Japan.
² Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan.

Abstract

In this study, six-membered N-acyliminium ions were generated by the "indirect cation pool" method and reacted with several nucleophiles. These reactions afforded disubstituted piperidine derivatives with high diastereoselectivities and good to excellent yields. The conformations of the obtained N-acyliminium ions were studied by low temperature NMR analyses and DFT calculations and were found to be consistent with the Steven's hypothesis.

Keywords: N-acyliminium ion; NMR analysis; cation pool; conformation; electroorganic synthesis; piperidine.