EPR Evidence for the Origin of Nonlinear Effects in an Enantioselective Cu(II)-Catalyzed Spiroannulation

• Published in: ACS catalysis Vol. 9; no. 2; pp. 1224 - 1230
• Main Authors: Armstrong, Brittany M, Sayler, Richard I, Shupe, Benjamin H, Stich, Troy A, Britt, R. David, Franz, Annaliese K
• Format: Journal Article
• Language: English
• Published: American Chemical Society 01.02.2019
• Subjects: reaction mechanism; Lewis acid catalysis; copper(II)−BOX; nonlinear effect; EPR spectroscopy

Herein, we describe an enantioselective Cu­(II)-catalyzed spiroannulation of N-Boc-iminooxindoles with allylsilanes where a significant positive nonlinear effect (NLE) is observed. EPR spectroscopic studies of the copper­(II) species present under synthetically relevant conditions reveal explicit sp...