Figure 7: Experiment on repetitive substrate addition cycles.

Reaction conditions (first cycle): 1a (0.01 mmol, 1 mol%), 25 °C, Et2O (4.6 ml), 2a (1.0 mmol, 1.0 equiv.), 3 (2.0 mmol, 2.0 equiv.). Reaction conditions (second to ninth cycle): addition of 2a (1.0 mmol, 1.0 equiv.), 3 (2.0 mmol, 2.0 equiv.). The reaction was monitored by means of in situ FT-IR analysis.