Fig. 6: Mechanistic studies.

a X-ray structure of CuCl2/L1 and CuCl2/L9. b Nonlinear effects of the e.e. values of ligand L9 and product 3a. c Variations of CuCl2/L9 ratios of propargylic hydrazination of 1a and 2a. NMR yield. d UV–vis spectroscopy experiments with Cu complexes. e DFT calculations of the optimized structures for TS modes to chiral 3a catalyzed by benzylthio–PYBOX L4 in the absence of TFE. f DFT calculations of the optimized structures in the presence of TFE.