基于[4+1]、[2+2]或[3+2]反应构建杂环的新方法研究

本课题旨在研究基于烯酮类化合物三种新的[4＋1]、[2+2]或[3+2]型选择性成环反应。（1）α,β-不饱和酮与活泼亚甲基化合物在金属氧化剂存在下发生[4＋1]型自由基反应，研究反应的选择性，明确反应的机理，提供一种有效的二氢呋喃环衍生物合成方法。（2）通过α,β-不饱和酮与活泼亚甲基化合物的加成产物在碘存在下利用碱调控反应的选择性，建立高立体选择性合成取代环丙烷、氧杂环丁烷的有效方法。通过改变底物结构，探索在碘作用下由取代丙二酸酯与α,β-不饱和酮通过[2＋2]反应构建氮杂环丁烷、硫杂环丁烷的可能性。（3）探索在碘作用下通过[3＋2]反应构建含氧、氮或硫的五元杂环的新方法。

We aim to study three types of novel [4+1], [2+2] or [3+2] selective cyclization reactions based on the enones compounds in this project. (1) [4+1] radical reactions of α, β-unsaturated ketones with active methylene compounds in the presence of metal oxidants, investigating the reaction selectivity, mechanism and providing a novel method for constructing dihydrofuran skeleton. (2) Controlling the selective conversion of the Michael adducts of malonates with enones in the presence of iodine using adaptive base and establishing an effective method for synthesizing cyclopropane, oxetane, and α-hydroxylmalonate derivatives. Investigating the possibility of constructing new azetidines and thietanes skeleton through iodine-mediated [2+2] reaction by changing the structure of malonates. (3) Exploring a new method to construct the five-membered heterocycles containing the oxygen, nitrogen or sulfur atom through [3+2] reactions.