Studies On New Palladium-catalyzed Nitrene Transfer Reactions And Other Related Reactions

Recent decades, organic synthetic methodology, especially organometallic catalyzed organic synthesis, has developed impressively, which has greatly improved the traditional organic synthesis routes, and promoted the development of argricultural science, pharmaceutical science and material science, especailly provides new train of thought of new pesticides initiative. This paper presents the progress of argricultural chemicals via the developments of organometallic catalyzed organic synthesis.1.A new approach to Palladium nitrene, azides as the precursor1) Sulfonylurea compounds are not only hypoglycemic drugs which are widely used in the treatment of type II diabetes, but also a very important kind of herbicides in pesticides which occupies a large market share. We developed a novel product-assembled bimetallic palladium catalyzed sulfonylazide transfer reaction with σ-donor/n-acceptor ligand CO had been developed, which is advantageous in terms of its broad substrate scope, high efficiency, and mild conditions (atmospheric pressure of CO at room temperature). The accomplishment of Glibenclamide synthesis on gram-scale further revealed the practical utility of this procedure. Mechanistically, the generation of product sulfonylurea-assembled bridged bimetallic palladium species is disclosed as the crucial step for this catalytic cycle, which has been proven by control experiments, NMR spectrum, and HRMS analysis.2) Besides sulfonyl ureas, normal ureas also serve as the widely existed fragents in an array of biological pharmaceuticals. We developed a facile and efficient Pd/C-catalyzed carbonylation of both aliphatic and aromatic azides in the presence of amines. Functionalized unsymmetrical ureas were straightforwardly synthesized by using readily available and cheap azides with amines under CO atmosphere, with the extrusion of N2 as the only by-product. It was found that not only aryl azides, but also benzyl and alkyl azides were suited for this methodology. Another feature of this procedure was the employment of a highly efficient palladium charcoal catalytic system.2. The synthesis of natural products and its derivativesNatural product 3,7-dimethyl-7-hydroxy-2-(Z)-octenelactone was an unique natural product with seven-membered lactone, exhibiting good antifungal and antioxidant activities. Due to the photostabilities caused by the double bond in the molecule, the structure needs to be modified to enhance the activity and stability. So we chose this compound as a lead compound, retain its basic skeleton moiety, and replaced the double bond with a benzene ring,, hope to get the target compound 7-methyl-7- hydroxy-2,3- benzo octalactone. Using the (E)-2-(2-carboxyvinyl)benzoic acid or 2-methylbenzoic acid as the starting material, target compound 7-methyl-7-hydroxy-2,3-benzooctalactone was synthesized respectively. Then, we also prepared the derivatives of target compound. Besides, we explored the synthesis of optical active 7-methyl-7-hydroxy-2,3-benzooctalactone.