vic-Diphosphination of Alkenes with Silylphosphine under Visible-Light-Promoted Photoredox Catalysis

Nitrogen-Based Organofluorine Functional Molecules: Synthesis and Applications

Fluorine and nitrogen form a successful partnership in organic synthesis, medicinal chemistry, and material sciences. Although fluorine-nitrogen chemistry has a long and rich history, this field has received increasing interest and made remarkable progress over the past two decades, driven by recent advancements in transition metal and organocatalysis and photochemistry. This review, emphasizing contributions from 2015 to 2023, aims to update the state of the art of the synthesis and applications of nitrogen-based organofluorine functional molecules in organic synthesis and medicinal chemistry. In dedicated sections, we first focus on fluorine-containing reagents organized according to the type of fluorine-containing groups attached to nitrogen, including N-F, N-RF, N-SRF, and N-ORF. This review also covers nitrogen-linked fluorine-containing building blocks, catalysts, pharmaceuticals, and agrochemicals, underlining these components' broad applicability and growing importance in modern chemistry.

Dehydrogenative α,γ-Diphosphinylation of Allylamines Enabled by Photoinduced Cobaloxime Catalysis

A regioselective radical α,γ-diphosphinylation of allylamines with secondary phosphine oxides by photoinduced cobaloxime catalysis is described. The reaction tolerates a wide range of allylamines and phosphine oxides, affording α-amino diphosphine dioxides in moderate to good yields with hydrogen evolution. The synthesis of new diphosphine monoxide and diphosphine ligands and the promising antitumor activities of products demonstrate the great potential applications of this approach in catalysis and drug discovery. The detailed mechanism studies indicate that this reaction likely proceeds through a dehydrogenative allylic phosphinylation and nucleophilic addition process.

Construction of Bidentate Phosphines Enabled by Photoinduced Reductive Diphosphination of Alkenes

The diphosphination of alkenes through a radical pathway offers a promising approach for the rapid construction of aryl bisphosphines. However, such a synthetic strategy has not been successfully applied to the preparation of alkyl bisphosphines, partially due to the difficulties in the generation of phosphorus-centered radicals from common alkyl phosphine compounds. We herein demonstrate that this challenge can be overcome by hiring Janus-faced chlorophosphine as the phosphine source that can act as not only a radical precursor to generate phosphine-centered radicals but also a radicalphile to capture alkyl radicals. With this novel strategy, a photocatalyzed reductive diphosphination reaction has been established, allowing for a straightforward synthesis of both aryl and alkyl 1,2-bisphosphines from readily accessible alkenes and chlorophosphines.

Direct synthesis of phosphorotrithioates from [TBA][P(SiCl3)2] and disulfides

Sulfur-containing organophosphorus molecules have played a pivotal role in organic synthesis, pharmaceutical pesticides and functional materials, thereby motivating researchers worldwide to establish S-P bonds from more environmentally friendly phosphorus sources. In this study, a novel method was developed for constructing S-P bonds, specifically by reacting the inorganic phosphorus derivative TBA[P(SiCl₃)₂] with sulfur-containing compounds under mild conditions. This method demonstrates the advantages of low energy consumption, mild reaction conditions and environmental friendliness. Moreover, this protocol-as a green synthesis method to replace the use of white phosphorus in the production of organophosphorus compounds (OPCs)-achieved the functional conversion of "inorganic phosphorus to organic phosphorus", in line with the national green development strategy.

Metal-Free One-Pot Multi-Functionalization of Unsaturated Compounds with Interelement Compounds by Radical Process

In recent years, the importance of "environmentally friendly manufacturing" has been increasing toward the establishment of a resource-recycling society. In organic synthesis, as well, it is becoming increasingly important to develop new synthetic strategies with resource conservation and the recycling of elemental resources in mind, rather than just only synthesis. Many studies on the construction of frameworks of functional molecules using ionic reactions and transition-metal-catalyzed reactions have been reported, but most of them have focused on the formation of carbon-carbon bonds. However, it is essential to introduce appropriate functional groups at appropriate positions in molecules in order for the molecules to express their functions, and furthermore, the highly selective preparation of multiple functional groups is considered important for the creation of new functional molecules. In this review, we focus on radical reactions with high functional group selectivity and overview the recent progress in practical methods for the simultaneous introduction of multiple functional groups and propose future synthetic strategies that emphasize the recycling of elemental resources and environmental friendliness.

Photoinduced Bisphosphination of Alkynes with Phosphorus Interelement Compounds and Its Application to Double-Bond Isomerization

The addition of interelement compounds with heteroatom-heteroatom single bonds to carbon-carbon unsaturated bonds under light irradiation is believed to be an atomically efficient method to procure materials with carbon-heteroatom bonds. In this study, we achieved the photoinduced bisphosphination of alkynes using the phosphorus interelement compound, tetraphenyldiphosphine monosulfide (1), to stereoselectively obtain the corresponding (E)-vic-1,2-bisphosphinoalkenes, which are important transition-metal ligands. The bisphosphination reaction was performed by mixing 1 and various alkynes and then exposing the mixture to light irradiation. Optimization of the conditions for the bisphosphination reaction resulted in a wide substrate range and excellent trans-selectivity. Moreover, the completely regioselective introduction of pentavalent and trivalent phosphorus groups to the terminal and internal positions of the alkynes, respectively, was achieved. We also found that the novel double-bond isomerization reaction of the synthesized bisphosphinated products occurred with a catalytic amount of a base under mild conditions. Our method for the photoinduced bisphosphination of carbon-carbon unsaturated compounds may have strong implications for both organic synthesis and organometallic and catalyst chemistry.

Highly regio- and stereoselective phosphinylphosphination of terminal alkynes with tetraphenyldiphosphine monoxide under radical conditions

The homolytic cleavage of the P^V(O)–P^III bond in tetraphenyldiphosphine monoxide simultaneously provides both pentavalent and trivalent phosphorus-centered radicals with different reactivities. The method using V-40 as an initiator is successfully investigated for the regio- and stereoselective phosphinylphosphination of terminal alkynes giving the corresponding trans-isomers of 1-diphenylphosphinyl-2-diphenylthiophosphinyl-1-alkenes in good yields. The protocol can be applied to a wide variety of terminal alkynes including both alkyl- and arylalkynes.

Synthesis of DPPP- and DPPPEN-Type Bidentate Ligands by Ring-Opening Diphosphination of Methylene- and Vinylcyclopropanes under Visible-Light-Promoted Photoredox Catalysis

A ring-opening diphosphination of methylene- and vinylcyclopropanes with tetraaryldiphosphines (Ar₂P-PAr₂) has been developed to afford the corresponding 1,3-diphenylphosphinopropane- and 1,3-diphenylphosphinopentane-type bidentate ligands, respectively. The reaction proceeds under bromine cation-initiated, visible-light-promoted photoredox catalysis at ambient temperature. Owing to the ready availability of functionalized diphosphines, the electronically diverse MeO- and CF₃-substituted bidentate ligands are also easily prepared.

Reductive Rearrangement of Tetraphenyldiphosphine Disulfide To Trigger the Bisthiophosphinylation of Alkenes and Alkynes

The facile synthesis of organophosphorus compounds is of great importance for the development of new synthetic methods by using air-stable sources of phosphorus. In this respect, a synthetic method that is based on a reductive rearrangement and is capable of converting air-stable pentavalent phosphorus compounds into reactive trivalent phosphorus compounds is a powerful tool. Tetraphenyldiphosphine disulfide, which is a shelf-stable solid, was the focus of this study, and it was shown to undergo reductive rearrangement to trigger the bisthiophosphinylation of a variety of alkenes, such as terminal, cyclic, internal, and branched alkenes, 1,3-dienes, and terminal alkynes when exposed to light without any catalyst, base, or additive.

Synthesis of Bis(phosphanyl)alkane Monosulfides by the Addition of Diphosphane Monosulfides to Alkenes under Light

Bis-phosphanated compounds are regarded as the most ubiquitous privileged ligand structures in transition-metal catalysis. The development of highly atom economical reactions is of great importance for their syntheses because less atom economical methods often require complicated purification procedures under inert atmospheres to remove excess starting materials and byproducts. Herein, the photoinduced addition reactions of diphosphane monosulfides bearing P^V (S)-P^III single bonds to alkenes is disclosed. These reactions require only equimolar amounts of the diphosphane monosulfide relative to the alkene and facilitate highly selective introduction of two different types of phosphorus-containing groups, such as thiophosphoryl and phosphanyl groups, into a variety of alkenes without any catalyst, base, or additive.

Enantiodivergent synthesis of 1,2-bis(diphenylphosphino)ethanes via asymmetric [3 + 2]-cycloaddition

The present work provides efficient access to chiral 1,2-bis(diphenylphosphino)ethanes (DPPEs) directly from diphosphine oxide alkenes and azomethine ylides via asymmetric [3 + 2] cycloaddition. Both enantiomers of the products can be obtained in good to excellent diastereo- and enantioselectivities (up to >20 : 1 dr and 99% ee).

Visible photocatalysis of novel oxime phosphonates: synthesis of β-aminophosphonates

A novel oxime phosphonate was synthesized and used in the difunctionalization of alkenes to access β-functionalized phosphonates via visible-light-driven N-centered iminyl radical-mediated multiple bond cleavage and a recombination process.

Diphosphination of 1,3-Dienes with Diphosphines under Visible-Light-Promoted Photoredox Catalysis

A diphosphination of 1,3-dienes with tetraaryldiphosphines proceeds under Ir(ppy)₃-promoted photoredox catalysis to form the corresponding 1,4-diphosphino-2-butenes in good yields with good regioselectivity. The key to success is the addition of a Br⁺ additive. Subsequent double bond hydrogenation successfully delivers the 1,4-bis(diphenylphosphino)butane (DPPB) derivatives with uniquely large bite angles. Thus, the present method can provide a facile access to DPPB-type ligands, which are of great importance in transition metal catalysis, from readily available diene substrates.

Diphosphination of Arynes with Diphosphines

A diphosphination of arynes with diphosphines has been developed. The reaction of stable aryne precursors, 2-(trimethylsilyl)aryl triflates, with tetraaryldiphosphines proceeds in the presence of fluorine- or carbonate-based activators to deliver the corresponding diphosphinated products, sterically and electronically tuned 1,2-bis(diphenylphosphino)benzene (dppbz) derivatives, which can find wide application in transition metal catalysis and material science. Additionally, preliminary computational studies on the reaction mechanism are also reported.

Visible-light-induced tandem phosphorylation cyclization of vinyl azides under mild conditions

This method provides a visible-light-induced radical tandem cyclization for the synthesis of phosphorus phenanthridines with various nitrogen-containing substrates.