Synthetic studies of neoclerodane diterpenes from Salvia divinorum: role of the furan in affinity for opioid receptors - PubMed

Scheme 2

Reagents and conditions: (a) CDMT, NMM, EtSH, CH₂Cl₂, 88%; (b) Pd/C, Et₃SiH, CH₂Cl₂, 82%; (c) 9-(1R, 2R-pseudoephedrinyl)-(10S)-(trimethylsilyl)-9-borabicyclo[3.3.2]decane, allylMgBr, Et₂O; (d) 1. (R)-(+)-α-Methoxy-α-trifluoromethylphenylacetic acid, oxalyl chloride, benzene; 2. DMAP, NEt₃, CH₂Cl₂, 82%; (e) acryloyl chloride, DMAP, Et₃N, CH₂Cl₂, 40%; (f) Grubbs II, CH₂Cl₂, 58%; (g) Appropriate Wittig reagent; (h) 1. EDCI, C₆H₅C(NH₂)=NOH, CH₂Cl₂; 2. Toluene, heat