Design, Synthesis And Applications Of Xiang-Phos:a Novel Chiral Monophosphine Ligand For The Enantioselective Intermolecular Cycloadditions With N-Allenamides

Recent years, with the demand of applications of chiral drug molecules an d chiral natural products continued to expand, asymmetric catalysis plays a mor e and more important role in organic chemistry. Scientists and scholars are co mmitted to the development of new effective catalyst. In this background, team s of the chiral phosphine ligands are growing as they play an important role i n pushing forward of asymmetric catalysis process.In this paper, we firstly designed and synthesized a series of novel chiral monophosphine ligands based on the reform of Ming-Phos which developed by our group. The ligands were obtained in good yields with high diastereoselecti vity from commercial available and cheap bromobenzaldehyde, di-1-adamantylph osphine and (R)-(+)-2-methyl-2-propanesulfinamide in only a few steps.Secondly, heterocyclic and polycyclic structures contains indoles and carbazole are present in most natural synthetic molecules with important biological activity. As a result, many scholars are attaching great importance to these compounds and exploring effective methods to synthesize them actively. When applying our novel chrial monophosphine ligands in gold-catalyzed [2+2] cycloadditions of 3-styrylindoles with N-allenyl oxazolidinone, we could obtain the cyclization products containing indoles with excellent diastereoselectivity and good enantioselectivity.Finally, we also applying our novel chrial monophosphine ligands in gold-catalyzed [4+2] cycloadditions of 2-styrylindoles with N-allenyl oxazolidinone. The products containing carbazole structure could be obtained with excellent diastereoselectivity and good enantioselectivity. Meanwhile, it was noteworthy that this is the first example of enantioselective [4+2] cycloaddition of 2-styrylindoles with N-allenamides.