Highly diastereoselective synthesis of manoyl oxide derivatives by TiCl4-catalyzed nucleophilic cleavage of ambracetal derivatives

摘要

The treatment of acetal 11 with KCN and AlCNEt2 in the presence of TiCl4 produces in high diastereoselectivity 2-cyanooxane 14, which can be easily converted into manoyl oxide derivatives. Using this strategy, 19-hydroxymanoyl oxide 20, diterpene from P. viscosum, was prepared from communic acids 7a-c after an 8-steps sequence in a 17% overall yield. [References: 43]