Yuqiu Wu

Rhazinilam and quebrachamine derivatives from Yunnan Kopsia arborea.

Three new rhazinilam-derived alkaloids, kopsiyunnanines C1, C2, and C3, and a new quebrachamine-type alkaloid, kopsiyunnanine D, which possess an unusual methoxymethyl or ethoxymethyl function, were isolated from the aerial parts of Yunnan Kopsia arborea. This is the first report of the presence of these functions in natural alkaloids. The structures and absolute configurations of the alkaloids were determined by spectroscopic methods and confirmed by semisynthesis.

Asymmetric total synthesis of novel pentacyclic indole alkaloid, kopsiyunnanine E, isolated from Kopsia arborea.

A new pentacyclic indole alkaloid, kopsiyunnanine E, was isolated from Yunnan Kopsia arborea, and its structure, which was inferred from spectroscopic data, was established by a 16-step asymmetric total synthesis that proved that the natural alkaloid was not enantiomerically pure.

Kopsiyunnanines F and isocondylocarpines: new tubotaiwine-type alkaloids from Yunnan Kopsia arborea.

Five new alkaloids, including three 19,20-epoxytubotaiwine stereoisomers, viz. kopsiyunnanines F1 (1), F2 (2), and F3 (3), (Z)-isocondylocarpine (4), and (Z)-isocondylocarpine N-oxide (5), along with five known tubotaiwine-type indole alkaloids were isolated from the aerial part of Yunnan Kopsia arborea Blume (Apocynaceae). Their structures including absolute configurations were elucidated by spectroscopic and chemical means.

Asymmetric Total Synthesis of Pentacyclic Indole Alkaloid Andranginine and Absolute Configuration of Natural Product Isolated from Kopsia arborea

The first asymmetric total synthesis of andranginine (1) via an asymmetric Morita-Baylis-Hillman reaction and a diastereoselective intramolecular Diels-Alder reaction has revealed that natural andranginine (1) isolated from Kopsia arborea existed as a scalemic mixture and contained predominantly the (16R,21S) form rather than the (16S,21R) form.