| Hypervalent iodine(â…¤)compounds IBX and DMP regarded as environmental-friendly metal-free oxidation regents have wide applications in the field of organic synthesis.Due to the special reaction mechanism,they render substrates highly chemical selectivity and demonstrate great advantages in the synthesis of specific compounds and multi-bonds transformations.The purpose of the present review is to summarize the hypervalent iodine compounds in the field of organic synthesis in the last ten years,especially focus on their synthetic application and space structure;there are lots of reaction examples to illustrate the incomparable merits of organic hypervalent iodine compounds in the synthesis of some drugs and natural products.Nitrogen-containing heterocycles such as N-arylpyrroles, N-arylindoles,and N-arylimidazoles,are an important class of compounds that are ubiquitous in numerous natural products and biologically active pharmaceuticals.1999,Stephen L.Buchwald reported that ligands can greatly accelerate the ullmann-Goldberg coupling reactions with extended scope of substrates and highly yields of products under mild reaction conditions.Since then, the use of ligands to facilitate the copper-catalyzed N-arylation of nucleophiles with aryl halides is one of the hottest branches of research in the formation of functionalized nitrogen-containing structures.This short review summarized the newly-developed ligands and estimated the catalyst systems in briefly.In this part,we have conducted a synthetic investigation on oxidation of anilines via IBX and DMP in metal-free systems and developed a facile protocol of synthesis of iminoquinones.The structure of the newly-found compounds is confirmed by single crystal diffraction analysis;the possible mechanism also is postulated.The experiment results demonstrated that the first class anilines can be converted to their corresponding compounds in excellent yields under very mild reaction conditions.Except for the products of iminoquinones,two special compounds 1 -Amino-5-Aza-10,11-Dithia-Dibenzo[a,d]Cyclohepten-2-One and 4,4'-Diaminoazobenzene are obtained,which have the application in the pharmacy and material science.As for the second class anilines,the specific substitute of p-MeO is required,and solvent system has important effect on the transformation.Indole regarded as second anilines is tested,and converted to indoline-2,3-dione in the presence of hypervalent iodine reagents.N-Hydroxyimides used as radical initiators in many oxidation reactions,such as oxidizing toluene,alcohols and silicon ester to carbonyls.In the present research, N-Hydroxyimides are applied as ligands in the coupling reaction of CuI-catalyzed arylation of N-arylpyrroles,N-arylindoles,and N-arylimidazoles.The catalyst system displayed great efficiency on the broaden scope of substrate in the mild reaction conditions,especially;amination of some of inactive halides also can be accelerated. We believe that these O-O donor compounds are of great importance to the research and development of ligands in the metal-catalyzed reactions.Oxazolidin-2-one is a common used nucleophile as C-N coupling partner.As documented that the access to a molecule containing the unit of oxazolidin-2-one is more efficient than others.So it is concerned that the five-member substrate has the facility to chelate with copper salts and promote the coupling reactions.Through the systematic and rational design of oxazolidin-2-one based structures,series of derivatives were synthesized.The experiment process demonstrated that the skeletal divergence of ligands in this transformation suggested a significant different result.In conclusion,the five member ring and the O or N atom are the key factors for the success of C-N coupling reactions.Finally,we have disclosed that oxazolidin-2-one acted as a versatile and efficient ligand for the CuI-catalyzed Ullmann reaction, Goldberg and cyclization of ortho-halobenzanilides.
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