Fig. 3: Mechanistic studies.
From: The catalytic asymmetric polyene cyclization of homofarnesol to ambrox
a, Mechanistic scenarios for a concerted and a stepwise pathway. b, 13C KIEs observed at natural abundance in recovered 1a. The experiment was performed in duplicate and the standard deviation is shown. c, Deuterium-labelling study in PFTB-d1 at −40 °C using (S,S)-IDPi catalyst 8g or (S)-PADI catalyst 9 with the respective 2H{1H} NMR spectrum of the tricyclic ether fraction. d, Polyene cyclization of all possible homofarnesol diastereomers to the corresponding tricyclic ethers and rationalization of the obtained products by the respective transition states according to the Stork–Eschenmoser hypothesis.
