Splitting the Phosphorus Bridge of 7‐Phosphanorbornadiene Complexes by Fluoride Ion

Abstract

The reaction of fluoride ion with 7‐phosphanorbornadiene P–W(CO)5 complexes yields fluorophosphido complexes which, in turn, can attack a second molecule of 7‐phosphanorbornadiene to give a fluorobiphosphine complex. The corresponding anion displays a huge P–P coupling. The structure of the anionic chromium analogue has been investigated by DFT calculations. The P–P bond is relatively short at 2.20 Å and displays a huge polarity suggesting an interesting chemistry. When the 7‐phosphanorbornadiene P‐substituent is 2‐chloroethyl, the attack of the fluoride ion is followed by a cyclization and a reductive dimerization leading to the first known biphosphirane complex.

Strong Evidence for a Transient Phosphinidenoid Complex

“…[8] For the Cu I -catalyzed reaction of 7-phosphanorbornadiene complexes with alkenes, a reaction discovered by Mathey and Marinetti in 1984, [9] , Lammertsma et al [10] proposed that the phosphinidenoid [W(CO) 5 + was most probably the counterion. [11] We gained access to [W(CO) 5 {RP-(CNLi)( [12]crown-4)}] [12] (R = CH(SiMe 3 ) 2 ), the first structural isomer of a phosphinidenoid complex (III). Herein, we present a method to generate phosphinidenoid-transitionmetal complexes under very mild conditions that can undergo selective substitution reactions and behave like a terminal phosphinidene complex.…”

“…In turn, Mathey and Compain generated the short-lived phosphanide complex [W(CO) 5 {PhP(F)}] À which acts as a strong anionic nucleophile; [Cs([18]crown-6)] + was most probably the counterion. [11] We gained access to [W(CO) 5 {RP-(CNLi)([12]crown-4)}] [12] (R = CH(SiMe 3 ) 2 ), the first structural isomer of a phosphinidenoid complex (III). Herein, we present a method to generate phosphinidenoid-transitionmetal complexes under very mild conditions that can undergo selective substitution reactions and behave like a terminal phosphinidene complex.Deprotonation of chloro(organo)phosphane complex 1 [13] with lithium diisopropylamide (LDA) in the presence of [12]crown-4 selectively generated complex 2 (Scheme 2).Warming up the reaction mixture to ambient temperature in the absence of any trapping reagents led to E-diphosphene complex 3 [14] and a product that is unstable at room temperature and which has a signal in the 31 P NMR spectrum at d = 347.7 ppm (Et 2 O, product ratio 4:1) with small phosphorustungsten coupling constants of 143.7 and 103.0 Hz.…”

“…In turn, Mathey and Compain generated the short-lived phosphanide complex [W(CO) 5 {PhP(F)}] À which acts as a strong anionic nucleophile; [Cs( [18]crown-6)] + was most probably the counterion. [11] We gained access to [W(CO) 5 {RP-(CNLi)([12]crown-4)}] [12] (R = CH(SiMe 3 ) 2 ), the first structural isomer of a phosphinidenoid complex (III). Herein, we present a method to generate phosphinidenoid-transitionmetal complexes under very mild conditions that can undergo selective substitution reactions and behave like a terminal phosphinidene complex.…”

Chemischer Nachweis eines transienten Phosphinidenoid‐ Komplexes

“…[21] Die À , in der sich gleichfalls eine deutliche Verzerrung der äquatorialen Carbonylliganden in Richtung Phosphoratom findet; das HOMO wurde dem ausgeprägten freien Elektronenpaar am Phosphoratom zugeordnet. [11] Koordination von [12]Krone-4 an das Lithiumion von 2' (Abbildung 2) vergrößert den P-Li-Abstand von 2.416 (in 2') auf 2.652 (in 2) und den P-Cl-Abstand von 2.160 (2') auf 2.217 (2), während die Verzerrung der äquatorialen Carbonylliganden verschwindet (Abbildung 2 …”

Template effects on the asymmetric cycloaddition reaction between 3,4-dimethyl-1-phenylarsole and diphenylvinylphosphine and their arsenic elimination reaction

“…Compared to the stable phosphole complexes in which a few phosphorus elimination reactions have been reported [2][3][4], arsenic elimination appeared to be a common phenomenon in the cycloaddition reactions involving arsoles [5][6][7]. For example, 2,3,4,5-tetramethyl-1-phenylarsole and 1,2,3,4,5-pentamethylarsole metal complexes readily undergo Diels-Alder reaction with acetylenedicarboxylic acid dimethyl ester.…”