Convenient synthesis of tropos phosphine-oxazoline ligands

Abstract

Tropos phosphine-oxazoline ligands have shown interesting coordination behavior and excellent chiral inducing ability in asymmetry catalysis. Here we present a convenient and economic route for the synthesis of this type of ligands. According to this new route, the ligands with different electronic and steric properties have been prepared successfully.tropos phosphine-oxazoline ligands, chirality-inducement, electronic property, steric property

Ir(III)-Catalyzed Direct C–H Functionalization of Arylphosphine Oxides: A Strategy for MOP-Type Ligands Synthesis

“…2′-Phosphorylbiphenyl-2-ol compounds as the P,O-ligand precursor have not only been used to synthesize different MOP-type ligands, but are also easier to modify and convert into a variety of other ligands or organocatalysts . At present, reported methods ( A , Scheme ) for the synthesis of 2′-phosphoryl biphenyl-2-ol involve: phosphinylation of binaphthyl skeletons, Diels–Alder cycloaddition reaction of tetracyclone and functional aromatic acetylenes, Pd-catalyzed Suzuki–Miyaura coupling between an aryl metal and an aryl halide or pseudohalides and ring opening of dibenzooxaphosphinine chloride with Grignard reagent . We have also achieved a R 2 (O)­P-directed Pd­(II)-catalyzed C–H direct hydroxylation to synthesize various substituted 2′-phosphorylbiphenyl-2-ol compounds .…”

“…3 At present, reported methods (A, Scheme 1) for the synthesis of 2′-phosphoryl biphenyl-2-ol involve: phosphinylation of binaphthyl skeletons, 4 Diels−Alder cycloaddition reaction of tetracyclone and functional aromatic acetylenes, 5 Pd-catalyzed Suzuki−Miyaura coupling between an aryl metal and an aryl halide or pseudohalides 6 and ring opening of dibenzooxaphosphinine chloride with Grignard reagent. 7 We have also achieved a R 2 (O)P-directed Pd(II)catalyzed C−H direct hydroxylation to synthesize various substituted 2′-phosphorylbiphenyl-2-ol compounds. 8 Despite such important advances, using simple, cheap triphenylphosphine oxide (Ph 3 PO) to synthesize 2′-phosphorylbiphenyl-2ol compounds via the C−H activation appears undoubtedly as a concise and highly efficient method, but which has yet to succeed due to uncontrolled regioselectivity and a lack of an appropriate pattern of activation.…”

Insertion of Arynes into P–O Bonds: One-Step Simultaneous Construction of C–P and C–O Bonds

“…Considering the importance of ortho -substituted arylphosphorus compounds, we transformed phenol 3a into triflate 10 , which could be easily employed for various transition-metal-catalyzed coupling reactions. For example, the respective transformations of triflate 10 into olefin 12 and biphenyl 15 by Stille and Suzuki couplings could lead to alternative routes to tertiary phosphine 13 and a series of phosphine–oxazoline derivatives, which are examples of useful ancillary ligands in homogeneous catalysis. Other transformations involved the methylation of phenolic hydroxyl group leading to compound 16 and subsequent nucleophilic aromatic substitution to produce chiral aminophosphine ligands or easy modification to access kinds of functionalized compounds …”