Quaternary Phosphonium Carboxylates: Structure, Dynamics and Intriguing Olefination Mechanism

We have earlier shown how the Wittig chemistry can be done using novel Eigenbase phosphonium carboxylate reagents. Here we discuss the phenomenon of ion pairing, their solution tautomerism, solid-state structure, and mechanistic aspects of olefination. The results point to a complex process involving unfamiliar H-bond-driven ion-pair equilibria followed by standard Wittig reaction steps.

Synthesis and Discovery of Schiff Base Bearing Furopyrimidinone for Selective Recognition of Zn2+ and its Applications in Cell Imaging and Detection of Cu2+

A simplefuro [2,3-d]pyrimidinone-based Schiff base FPS was synthesized via aza-Wittig reaction and structure elucidation was carried out by spectroscopic studies FT-IR, 1H NMR, and 13C NMR and mass spectrometry. FPS showed weak fluorescence emission in methanol and the selectivity of FPS to different metal ions (Mn2+, Ca2+, Fe2+, Fe3+, Mg2+, Al3+, Ba2+, Ag+, Co2+, Na+, K+, Cu2+, Zn2+, Pb2+, Bi3+) were studied by absorption and fluorescence titration. The results show that FPS has selective fluorescence sensing behavior for Zn2+ ions and the limit of detection (LOD) was calculated to be 1.19 × 10–8 mol/L. Moreover, FPS-Zn2+ acts as a metal based highly selective and sensitive new chemosensor for Cu2+ ions and the LOD was calculated to be 2.25 × 10–7 mol/L. In accordance with the results and theoretical calculations, we suspected that the binding mechanisms of FPS to Zn2+ and Cu2+ were assigned to be the cooperative interaction of Zn2+(Cu2+)-N.

One-Pot Synthesis of 3-(1,2,3,4-Tetrahydroisoquinolin-1-yl)-isoquinolin-1(2H)-ones by Sequential DEAD-Promoted Oxidative Ugi/Wittig Reaction Starting from Phosphonium Salt Precursors

A new one-pot Synthesis of 3-(1,2,3,4-tetrahydroisoquinolin-1-yl)- isoquinolin-1(2H)-ones by DEAD-promoted oxidative Ugi/Wittig reaction was developed. The sequential reactions of (2-carboxybenzyl)triphenylphosphonium salts, isocyanides and N-aryl-1,2,3,4-tetrahydroisoquinolines produced 3-(1,2,3,4-tetrahydroisoquinolin-1-yl)- isoquinolin-1(2H)-ones in moderate to good overall yields in the presence of DEAD and Et3N.

The Phospha-Bora-Wittig Reaction

Here, we report the phospha-bora-Wittig reaction for the direct preparation of phosphaalkenes from aldehydes, ketones, esters, or amides. The transient phosphaborene Mes*P=B-NR2 reacts with carbonyl compounds to form 1,2,3-phosphaboraoxetanes, analogues of oxaphosphetane intermediates in the classical Wittig reaction. 1,2,3-phosphaboraoxetanes undergo thermal or Lewis acid/base-promoted cycloreversion, yielding phosphaalkenes. Experimental and density functional theory studies reveal far-reaching similarities between classical and phospha-bora-Wittig reactions.

The Phospha-Bora-Wittig Reaction

Here, we report the phospha-bora-Wittig reaction for the direct preparation of phosphaalkenes from aldehydes, ketones, esters, or amides. The transient phosphaborene Mes*P=B-NR2 reacts with carbonyl compounds to form 1,2,3-phosphaboraoxetanes, analogues of oxaphosphetane intermediates in the classical Wittig reaction. 1,2,3-phosphaboraoxetanes undergo thermal or Lewis acid/base-promoted cycloreversion, yielding phosphaalkenes. Experimental and density functional theory studies reveal far-reaching similarities between classical and phospha-bora-Wittig reactions.