Asymmetric Total Synthesis Of Three Dimeric Hexahydropyrroloindole Alkaloids And Two Aza-[6,5,6]-tricycles & Synthetic Study On Alsmaphorazine B

This dissertation focused on:(1) Total synthesis of (+)-chimonanthine, (+)-folicanthine, and (-)-calycanthine; (2) Asymmetric synthesis of common aza-tricyclic core of various alkaloids; (3) Synthetic study towards alsmaphorazine B.In chapter 1, a facile, straightforward and enantioselective total synthesis of (+)-chimonanthine, (+)-folicanthine, and (-)-calycanthine were accomplished in 4-5 steps from commercially available tryptamine. The synthesis features copper-mediated asymmetric cyclodimerization of chiral tryptamine derivative, an unprecedented base induced skeleton isomerization, and a chemo-selective methylation. The successful development of a chiral auxiliary introduction strategy was proved to be feasible for the synthesis of these natural products.In chapter 2, the asymmetric synthesis of common aza-tricyclic core of different types of natural alkaloids had been accomplished from commercially available L-Cbz-tyrosine. This practical approach was capable of generating scale-up aza-tricyclic skeleton. Meanwhile, it will facilitate the manipulating functionalities on the aza-tricyclic framework further, for the purpose of target-oriented synthesis of a large number of different natural alkaloids containing this versatile aza-tricyclic structure.In chapter 3, synthetic study towards alsmaphorazine B was decribed. We focused on the synthesis of cage-like right hemisphere of alsmaphorazine B from commercially available L-tryptophan or its direvatives.