Iron Catalyzed C-c Bond Coupling,

Metal catalysts are very important to synthetic organic chemists. The development of more efficient, easily recyclable and environmentally benign catalysts with high selectivities has drawn much attention to chemists. However, many catalysts are derived from heavy or rare metals, the toxicity and high-cost restrict their large-scale applications. In contrast, iron is one of the most abundant metals on earth, and consschemeuently one of the most inexpensive and environmentally friendly ones. Recently, iron-catalyzed reactions have drawn much attention in organic chemistry , because iron compounds are usually low-cost, easily available and environmentally friendly which are compared to other metals, such as gold, silver, palladium et al. Many efficient cross-coupling reactions of construction of C-N, C-O,C-S,C-C bonds catalyzed by iron have been developed in recent years. In this thesis, some iron-catalyzed C-C bond formation reactions have been described. There are four parts in this thesis.1. The overviews of iron-catalyzed C-C bond coupling reactions In this section, an overview of recent C-C bond formation reactions such as cycloaddition reactions,substitution reaction and cyclization reactions catalyzed by iron have been demonstrated.2. An efficient and mild iron-mediated synthesis of alkenyl halides via direct C–C bond formation of benzyl alcohols and aryl alkynes. By taking advantage of the high activity of benzyl alcohols to Lewis acid, we successfully accomplished an efficient and mild method for preparing alkenyl halides via direct C–C bond formation of benzyl alcohols and aryl alkynes in CH2Cl2 by using 50 mol % of FeCl36H2O or 50 mol % FeBr3.3. A mild and efficient iron-catalyzed synthesis of alkenyl halides via direct addition of benzyl halides to arylalkynes The development of direct C-C bond formation processes that using sustainable, environmentally benign and low-cost catalysts is a critical challenge for organic synthetic chemists. Recently, some efficient iron-catalyzed systems have been explored for carbon-carbon couplings. We have successfully accomplished an efficient and mild synthesis of alkenyl halides via addition of benzyl halides to arylalkynes by using 5 mol% of FeCl36H2O as the active catalyst.4. An efficient and mild iron-catalyzed direct allylation of benzyl alcohols and benzyl halides with allyltrimethylsilaneIn the past years, some efficient methods have been explored to prepare terminal olefins via direct allylation of benzyl alcohols with allyltrimethylsilane. However, many of these systems suffer from hash reaction conditions and relatively expensive metal catalysts. Therefore, development of more efficient and mild catalysts to promote the direct allylation of benzyl alcohols remains attractive. An efficient and mild iron-catalyzed direct allylation of benzyl alcohols and benzyl halides with allyltrimethylsilane has been developed. The present method would provide an excellent alternative to systems reported before due to its nearly quantitative yields, sustainable catalyst and mild conditions.