稠环偕二卤代环丙烷是一类制备简单且潜力巨大的有机结构，深入拓展该类化合物在有机合成中的应用，对提高合成效率，发展简洁、多样化合成策略具有十分重要的意义。本项目拟应用稠环偕二卤代环丙烷不对称开环反应为关键步骤，完成一系列具有显著生物活性的石蒜科生物碱、吗啡及倍半萜类天然产物liriosmaside A的不对称全合成。具体内容为：（1）在代表性稠环偕二卤代环丙烷6,6-二溴双环[3.1.0]己烷的开环反应中，以商品化手性胺进攻其π-烯丙基碳正离子，生成对映体纯开环产物，结合分子内Alder-Ene反应及官能团转化策略，完成超过6个具有优良生物活性的石蒜科生物碱的全合成；（2）深入拓展取代6,6-二溴双环[3.1.0]己烷的开环反应，探索迄今最为简短的吗啡全合成路线；（3）构建高度官能化的稠环偕二卤代环丙烷，并应用其扩环策略从而实现倍半萜类天然产物liriosmaside A的首次全合成。

Ring-fused gem-dihalocyclopropanes are important substrates with ready availability and great potentials in chemical synthesis. Due to their versatile chemistry, they have wide-spread applications in the development of high efficient, concise and divergent synthetic strategies. In current application, the asymmetric total syntheses of several bioactive Amaryllidaceae alkaloids, morphine, and recently isolated sesquiterpenoid tropolone glycoside liriosmaside A based on the ring-opening reaction of certain ring-fused gem-dihalocyclopropanes are proposed. In broad terms there are three major components to the proposed program of work outlined below, the first being focused on the development of the first asymmetric ring-opening methodologies using chiral amines as nucleophiles to trap the π-allyl cation formed as a result of the ring-opening process of 6,6-dibromobicyclo[3.1.0]hexane. This will allow for the preparation of enantiomer pure ring-opening products that, when in combination of an intramolecular Alder-Ene reaction and functional group interconversions (FGIs), leads to synthesize a variety of Amaryllidaceae alkaloids. The second content will be exploring the asymmetric ring-opening strategy of certain substituted 6,6-dibromobicyclo[3.1.0]hexane to have the morphine skeleton built, during which an intramolecular Heck alkenylation reaction and Eschenmoser–Claisen rearrangement will be employed, and the shortest asymmetric total synthesis of morphine is expected to achieve. In the last program, a highly functionalized ring-fused gem-dihalocyclopropanes will be prepared so as to complete the first total synthesis of sesquiterpenoid tropolone glycoside liriosmaside A by utilizing a ring-expansion reaction.