Synthesis of Lycorine

Abstract

Alkaloids are a type of natural products which can be isolated from many kinds of creature such as plants, animals, fungi, and bacteria. These kinds of natural products possess interesting biological activities for instance anticancer, antiflamatory, and antimalarial. Because of the useful properties, scientists including the synthetic chemists intensely pay attention to alkaloids. They have attempt to synthesize natural and unnatural analogues of alkaloids. One of the most commom reaction for synthesis alkaloids is the N-acyliminium ion cyclization.

This thesis reports a synthetic study of alkaloids. The alkaloid is lycorine which is found in the Amaryllidaceae family as Clivia miniata and Daffodil bulb. The structure is a pentacyclic benzoindolizidine structure containing four stereo centers. The heck reaction and N-acyliminium ion cyclization were applied as the crucial reactions for the synthetic route. The synthetic strategy of lycorine was designed in two synthetic routes. First, the construction of the tricyclic core from N-acyliminium ion cyclization. However, this result was observed without the hydroxylactam peak of the carbon NMR spectrum at 76.5 ppm. And second, the synthesis involved Suzuki reaction followed by metathesis for generated tricyclic core from N-acyliminium ion cyclization but metathesis did not give the desired product. Now, an alternative route devised and it involves witting olefination and metathesis for generating a C-C bond linkage.

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