Crystal, Solution, and Computational Study of the Structure of Ortho-Lithium N,N-Diisopropyl-P,P-Diphenylphosphinothioic Amide

The first crystal structure of an ortho-lithium phosphinothioic amide complexed with tetramethylethylenediamine 12 is reported. The complex consists of a spirane in which the spiro-lithium is N,N- and C,S-chelated by the diamine and organophosphorus ligands, respectively. The analogous ortho anion 14 obtained by Sn(IV)/Li transmetallation in THF has also been synthesized. Nuclear magnetic resonance study of both anions showed that they exist as monomers in solution and are involved in dynamic processes including the restricted rotation around the P-N bond. 14 is converted at room temperature by nucleophilic cyclization to the dearomatized anion 15, which evolves after a few hours to the benzophosphindole sulfide 16. Density functional theory calculations supported the aggregation state in solution and were used to explore the conformational space of anion 12, the mechanism of ortho-lithiation directed by P(X)-N (X=O, S) groups, and the mechanism of formation of 15.

A Powerful P-N Connection: Preparative Approaches, Reactivity, and Applications of P-Stereogenic Aminophosphines

For more than five decades, P-stereogenic aminophosphine chalcogenides and boranes have attracted scientific attention and are still in the focus of ongoing research. In the last years, novel transition metal-based synthesis methods have been discovered, in addition to the long-known use of chiral auxiliaries. Enantiomerically pure compounds with N-P+ -X- (X=O, S, BH3 ) motifs served as valuable reactive building blocks to provide new classes of organophosphorus derivatives, thereby preserving the stereochemical information at the phosphorus atom. Over the years, intriguing applications in organocatalysis and transition metal catalysis have been reported for some representatives. Asymmetric reductions of C=C, C=N, and C=O double bonds were feasible with selected P-stereogenic aminophosphine oxides in the presence of hydrogen transfer reagents. P-stereogenic aminophosphine boranes could be easily deprotected and used as ligands for various transition metals to enable catalytic asymmetric hydrogenations of olefins and imines. This review traces the emergence of a synthetically and catalytically powerful functional compound class with phosphorus-centered chirality in its main lines, starting from classical approaches to modern synthesis methods to current applications.

Copper(I)-Catalyzed Asymmetric Synthesis of P-Chiral Aminophosphinites

Herein, a copper(I)-catalyzed reaction of diarylphosphines and O-benzoyl hydroxylamines is developed. In the cases of symmetrical diarylphosphines, a series of aminophosphinites is prepared in high yields. In the cases of unsymmetrical diarylphosphines, an array of P-chiral aminophosphinites is synthesized in high yields with high enantioselectivity by using a copper(I)-(R,R_P )-Ph-FOXAP complex as a chiral catalyst. Based on several control experiments and ³¹ P NMR studies, a two-electron redox mechanism involving the dynamic kinetic asymmetric transformation of unsymmetrical diarylphosphines is proposed for the copper(I)-catalyzed asymmetric reaction. Finally, one representative P-chiral phosphoric amide generated through the oxidation with H₂ O₂ is transformed to a chiral diarylphosphinate in high yield with retained enantioselectivity, which allows further transformations towards various P-chiral tertiary phosphines.

Taking Advantage of Ortho- and Peri-Substitution to Design Nine-Membered P,O,Si-heterocycles*

A family of cyclic phosphine-disiloxane featuring peri-substituted naphthyl(Nap)/acenaphthyl(Ace) scaffolds has been prepared and fully characterized including X-ray structure, which enables a detailed structural analysis. This straightforward synthesis takes advantage of both ortho- and peri-substitution of Nap/Ace-substituted phosphine oxides. The synthetic method allows diversifying the polycyclic aromatic platform (Nap and Ace) as well as the Si substituents (Me and Ph). Despite a strong steric congestion, the P-atom remains reactive toward oxidation or coordination. In particular, Au(I) complex could be prepared. All the compounds display absorption/luminescence in the UV-Vis range. Surprisingly, the P-trivalent derivatives display unexpected luminescence in the green in solid-state.

Synthesis, crystal structures and magnetic properties of a P-stereogenic ortho-(4-amino-tempo)phosphinic amide radical and its CuII complex

The synthesis of phosphinic amides containing one 4-amino-TEMPO substituent at the ortho position has been achieved through copper(i) catalyzed cross-coupling reactions of ortho-iodophosphinic amides with 4-amino-TEMPO. The method has been extended to the preparation of the first example of a P-stereogenic ortho-(4-amino-tempo)phosphinic amide radical 10. The reaction of 10 with Cu(hfac)2 afforded the P-stereogenic CuII complex 19. The crystal structure of both chiral compounds is reported. The molecular structure of 10 consists of a supramolecular zig-zag chain formed by intermolecular hydrogen bonds between the NH group of the phosphinic amide moiety and the nitroxide oxygen atom. In complex 19, the ligand acts as a bridge between two CuII ions coordinated to the oxygen atoms of the P[double bond, length as m-dash]O and N-O· groups leading to the formation of a polymeric helicate chain in which the metal ions exist in a distorted octahedral geometry. The magnetic behavior of ligand 10 is characterized by very weak intermolecular antiferromagnetic interactions, whereas ferro- and anti-ferromagnetic interactions are present in complex 19.

Recent advances in the synthesis of organophosphorus compounds via Kobayashi's aryne precursor: a review

This review systematically summarizes the progress in aryne chemistry for the synthesis of organophosphorus compounds via aryne insertion into the C–P, P–N, P–P, P–O, PP, PN and PS bonds.

New o-substituted diphenylphosphinic amide ligands: synthesis, characterization and complexation with Zn2+, Cu2+ and Y3+

Phosphinic amide derivatives have drawn significant attention in coordination chemistry and have been incorporated into the design and synthesis of new ligands.

Synthesis of P-Stereogenic Benzoazaphosphole 1-Oxides via Alkynylation of P-Stereogenic ortho-Aurated and ortho-Iodo Phosphinic Amides

An efficient methodology for the synthesis of P-stereogenic dihydrobenzoazaphosphole 1-oxides via intramolecular 5-exo-dig alkyne hydroamination promoted by tetrabutylammonium fluoride is herein described. The required chiral o-alkynylphosphinic amide starting materials were prepared in high yields under very mild reaction conditions through alkynylation of P-stereogenic (O^C)-cyclometalated (phosphinic amide)dichlorogold(III) complexes and Sonogashira cross-coupling of ortho-iodo P-stereogenic phosphinic amide.

Copper-Catalyzed Oxidative Alkylation (Methylation) of Phosphonamides and Phosphinamides Using Dicumyl Peroxide

An effective and practical CuI-catalyzed methodology toward N-alkyl or N-methyl phosphonamides and phosphinamides was herein demonstrated. The transformation took place readily under the oxidative conditions, and plenty of N-alkylated (methylated) amides (30 examples) were successfully furnished in high efficiency (up to 92% yields). Dicumyl peroxide was considered to act either as the oxidant for the alkylation reaction or as methyl donator for the methylation protocol.

Efficient synthesis of cyclic P-stereogenic phosphinamides from acyclic chiral precursors via radical oxidative intramolecular aryl C–H phosphinamidation

A highly efficient method for the synthesis of cyclic P-stereogenic phosphinamides from acyclic chiral precursors via radical oxidative C–H phosphinamidation, followed by the versatile synthesis of various P-stereogenic compounds, is presented.