... Volume: Page: ... The Lewis acids were chosen from three general categories, including (1) acids previously used in porphyrin synthesis, 15,23 - 25 (2) acids used in organic reactions such as ... 5, TMSOTf (10), −, 1, 26 (2), 29, SnCl 4 (25), Et 3 N (100), 90, 9. ...