Reactivity of Aromatic Phosphorus Heterocycles – Differences Between Nonfunctionalized and Pyridyl‐Substituted 2,4,6‐Triarylphosphinines

Abstract

Detailed studies on the reactivity of 2‐(2′‐pyridyl)‐4,6‐diphenylphosphinine (2) towards CF3SO3H and sulfur have been performed, and the results were compared with those for nonfunctionalized 2,4,6‐triphenylphosphinine derivatives. Substantial differences between these heterocycles were observed, and the reaction products could be characterized crystallographically. The reactions of 2,4,6‐triarylphosphinine sulfides with methanol led to different products, which could be characterized by NMR spectroscopy and X‐ray crystal structure analysis. Interestingly, the outcomes of these transformations strongly depend on the presence of an additional donor functionality within the phosphorus heterocycle as well as the nature of the solvent and the reaction temperature. DFT calculations were performed to rationalize the different reaction pathways.

Making Aromatic Phosphorus Heterocycles More Basic and Nucleophilic: Synthesis, Characterization and Reactivity of the First Phosphinine Selenide

“…Similarly, the P=C double bond in phosphinine sulfides is also prone to addition reactions in the presence of water or alcohols, as already demonstrated by us. [12b] …”

Unexpected Multiple Coordination Modes in Silyl-Bridged Bis(phosphinine) Complexes

“…Phosphinines (the phosphorus analogue of pyridine) are fascinating ligands in coordination chemistry because they contain phosphorus in an unusual, multiply bonded environment. − This gives them unique properties including diagnostic 31 P­{ 1 H} NMR resonances at high chemical shifts in an “aromatic” region and variable binding modes such as η 6 binding − and nondirectional η 1 binding. − Electronically, phosphinines function as π-accepting ligands − but can also function as noninnocent ligands due to facile nucleophilic attack at P under certain conditions. − Monodentate phosphinine ligands − and hybrid ligands, where the phosphinine is connected to another donor, − ,,− are being increasingly explored in coordination chemistry and catalysis; however, ligands based on multiple phosphinine units are much rarer. , Examples include a trans -coordinating diphosphinine, diphosphorus analogue of 2,2′-bipyridine ( A , tmbp: 4,4′,5,5′-tetramethyl-2,2′-biphosphinine, Chart ), ,, and very recent work on multidentate phosphanyl phosphinines . Using a very versatile diazaphosphinine methodology, − Mathey, Le Floch, and co-workers synthesized and studied the coordination chemistry of silyl-substituted multidentate phosphinine ligands with Ir, Rh, , Au, and W­(CO) 3 . , A bis­(phos­phinine) with a SiMe 2 linker and featuring 3,3′-Ph substituents was also synthesized (Chart , B ), and although its reduction chemistry was studied in detail...…”

Six-Membered Rings With One Phosphorus Atom

“…Methanol could be used as a suitable agent for the addition on the phosphorus-carbon double bond of phosphinines 113 (Scheme 46). 68 On the other hand, the oxidation can also be achieved by an exchange process from an aminophosphinine under acidic conditions. In particular, concentrated hydrochloric acid was used in the case of the λ 5 -phosphinine 115 to synthesize the corresponding ester 116.…”