Phosphine Oxides (-POMe2) for Medicinal Chemistry: Synthesis, Properties, and Applications

A general practical approach to hetero(aromatic) and aliphatic P(O)Me₂-substituted derivatives is elaborated. The key synthetic step was a [Pd]-mediated C-P coupling of (hetero)aryl bromides/iodides with HP(O)Me₂. The P(O)Me₂ substituent was shown to dramatically increase solubility and decrease lipophilicity of organic compounds. This tactic was used to improve the solubility of the antihypertensive drug prazosin without affecting its biological profile.

Rhodium(III)-Catalyzed Sequential C-H Activation and Cyclization from N-Methoxyarylamides and 3-Diazooxindoles for the Synthesis of Isochromenoindolones

An efficient synthetic method for structurally various isochromenoindolones has been demonstrated through Rh(III)-catalyzed C-H activation followed by a cyclization reaction of N-methoxyarylamides with 3-diazooxindoles. The sequential reaction involves the streamlined formation of C-C and C-O bonds in one pot. The present method provides a broad range of isochromenoindolones as a new privileged scaffold in moderate to good yields with the release of methoxyamine and molecular nitrogen and has the benefits of a broad substrate scope and good functional group tolerance.

Rhodium-Catalyzed Redox-Neutral Olefination of Aryldiazenes with Acrylate Esters via C-H Activation and Transfer Hydrogenation

Rh(III)-catalyzed redox-neutral C-H olefination of aryldiazenecarboxylates has been realized using arylate esters as the olefinating reagents. This reaction proceeds under mild and redox-neutral conditions, resulting in integration of C-H activation and transfer hydrogenation. The chemoselectivity complements that of previously reported rhodium-catalyzed coupling of the same substrates.

Copper-catalyzed arylation of polycyclic aromatic hydrocarbons by the P[double bond, length as m-dash]O group

The first example of a directed and regioselective arylation of polycyclic aromatic hydrocarbons (PAHs) by using a P[double bond, length as m-dash]O directing group is reported herein. The protocol uses a cheap copper catalyst, and results in a breakthrough meta-selective C-H functionalization of arylphosphine oxide compounds. Substrates with potential fluorescence properties, for example, pyrene and fluoranthene, were successfully arylated under the system, thus achieving an efficient modification of fluorescent molecules containing the P[double bond, length as m-dash]O functional group.

Late stage modifications of P-containing ligands using transition-metal-catalysed C–H bond functionalisation

Recent advances in C–H bond functionalisation of phosphorus derivatives are presented, with a special attention to preparation of phosphine ligands.

A theoretical study on the mechanism of ruthenium(ii)-catalyzed phosphoryl-directed ortho-selective C–H bond activations: the phosphoryl hydroxy group triggered Ru(ii)/Ru(0) catalytic cycle

A theoretical study on the mechanism of ruthenium(ii)-catalyzed phosphoryl-directed ortho-selective C–H bond activations has been reported.

Palladium-catalyzed R2(O)P directed C(sp2)-H acetoxylation

A novel and efficient Pd-catalyzed C-H acetoxylation is described. The approach uses R2(O)P as a directing group to synthesize various substituted 2'-phosphorylbiphenyl-2-OAc compounds. Notably, the reaction exhibits smooth operation under mild conditions and shows good functional group tolerance. Products are obtained with high selectivity and yields.

Palladium-catalyzed direct alkenylation of 2-methyl-4H-pyrido[1,2-a]pyrimidin-4-ones using oxygen as the oxidant

A direct C-3 alkenylation of 2-methyl-4H-pyrido[1,2-a]pyrimidin-4-ones through palladium-catalyzed C–H activation using oxygen as the terminal oxidant has been developed.

Transition metal-catalyzed C–H bond functionalizations by the use of diverse directing groups

In this review, a summary of transition metal-catalyzed C–H activation by utilizing the functionalities as directing groups is presented.

P(O)R2-directed Pd-catalyzed C-H functionalization of biaryl derivatives to synthesize chiral phosphorous ligands

Chiral phosphorus ligands have been widely used in transition metal-catalyzed asymmetric reactions. Herein, we report a new synthesis approach of chiral biaryls containing a phosphorus moiety using P(O)R₂-directed Pd-catalyzed C–H activation; the functionalized products are produced with good enantioselectivity.

Synthesis of ethoxy dibenzooxaphosphorin oxides through palladium-catalyzed C(sp(2))-H activation/C-O formation

We report an efficient Pd-catalyzed C(sp(2))-H activation/C-O bond formation for the synthesis of ethoxy dibenzooxaphosphorin oxides from 2-(aryl)arylphosphonic acid monoethyl esters under aerobic conditions.

Palladium-catalyzed P(O)R2 directed C–H arylation to synthesize electron-rich polyaromatic monophosphorus ligands

A novel pathway for the synthesis of polyaromatic monophosphorus ligands via the P(O)R₂ directed palladium-catalyzed arylation of (diisopropylphosphoryl)biphenyl skeleton derivatives was discovered.

Rhodium-catalyzed oxidative C-H activation/cyclization for the synthesis of phosphaisocoumarins and phosphorous 2-pyrones

Rhodium-catalyzed cyclization of phosphinic acids and phosphonic monoesters with alkynes has been developed. The oxidative annulation proceeds with complete conversion of phosphinic acid derivatives and allowed the atom-economic preparation of useful phosphaisocoumarins with high yield and selectivity. The reaction is tolerant of extensive substitution on the phosphinic acid, phosphonic monoester and alkyne, including halides, ketone, and hydroxyl groups as substituents. Furthermore, we found that alkenylphosphonic monoesters proceed to give a wide range of phosphorus 2-pyrones through oxidative annulation with alkynes. Mechanistic studies revealed that C-H bond metalation was the rate-limiting step.