Synthesis Of 3β-hydroxy-24-norchol-5-en-23-oic Acid And Studies On The Synthesis Of HIV-inhibitive Steroid Product OSW-1

This thesis aims at the studies on the total synthesis of 3β-hydroxy-24-norchol-5-en-23-oic acid,an anti-inflammatory marine natural product,and studies on the synthesis of HIV-inhibitive steroid product OSW-1,which consists of the following three chapters:ChapterⅠ:Synthesis of 313-hydroxy-24-norchol-5-en-23-oic acid.The synthesis of 3β-hydroxy-24-norchol-5-en-23-oic acid,an anti-inflammatory marine natural product,was achieved from commercial available 16-dehydropregnenolone acetate in six steps,which involved 1,2-selective reduction ofα,β-unsaturated ketones, acetyl-protected,asymmetric allyl alkylation,ester shedded,catalytic hydrogenation, deprotection,with a 28.2%overall yield.The key step was substrate-induced palladium catalyzed allylation.ChapterⅡ:Studies on the synthesis of HIV-inhibitive steroid product OSW-1.OSW-1 has a good selective anti-cancer activity,anti-HIV activity which arouses much attention.The development of OSW-1 was introduced simplely;The asymmetric synthetic route of OSW-1 was designed;The synthesis of key intermediate 73 from commercial available 16-dehydropregnenolone acetate as starting material in four steps, which involved selective reduction,acetyi-protected,asymmetric allyi alkylation, lengthening the carbonchain.ChapterⅢ:Asymmetric transition-metal-catalyzed allylic alkylations:applications in total synthesis(Review).This review briefed the mechanism of asymmetric transition-metal-catalyzed allylic alkylations,chiral ligands which utilized in natural products total synthsis,application of Mo,W-catalyzed allylic alkylations.Highlighted the carbon,oxygen,nitrogen,sulfur and so on as nucleophiles in Pd-catalyzed allylic alkylations which utilized in natural products total synthsis.This review involved nearly fifty total synthtic literature in the last two decades.