Fig. 2: Reaction optimization and scale-up.
From: The catalytic asymmetric polyene cyclization of homofarnesol to ambrox
a, Catalyst screening and optimization of the polyene cyclization of (3E,7E)-homofarnesol to (−)-ambrox. See Supplementary Information for details. b, Stacked gas chromatography traces of the crude reaction mixture obtained with PADI 9 (top) and IDPi 8g (middle) as catalysts. Enantiopure (−)-ambrox is shown as a reference (bottom). c, Scale-up of the catalytic asymmetric polyene cyclization in the presence of IDPi catalyst 8g in PFTB affording (−)-ambrox. d, Technical synthesis of (3E,7E)-homofarnesic acid 11 from (E)-nerolidol and catalytic asymmetric polyene cyclization of 11 to (+)-sclareolide. r.t., room temperature; d.r., diastereomeric ratio; e.r., enantiomeric ratio; e.e., enantiomeric excess.
