Synthesis and structural study of the first 1-phosphaallyl anion

Abstract

The allyl anion (I) and, in particular, the metal-stabilized ~3complexes are among the best explored carbanion systems.' In contrast, little is known about the phosphaallylic systems in which one carbon atom is replaced by a twofold coordinated phosphorus center (II, 111) (Scheme I). While the 2-phosphaallyl complexes ( 5 ) The coordination of lithium by thrce dme molecules is known: Baker, T.; Krusic, P. J.; Tulip, T. H.; Calabrcae, J. C.; Wreford, S . S . J. Am. Chem. Soc. 1983,105,6763. Altwood, J. L.; Rogers, R. D.; Vann Bynum, R. Cryst. Struct. Commun. 1!%4,40,1812. Schumann,H.;Nickel,S.;Hahn,E.;Heeg, M. J. Organometallics 1985, I , 800. Schumann, H.; Nickel, S.; Loebel, J.; Pickardt, J. Organometallics 1988, 7, 2004.

Phosphetes via Transition Metal Free Ring Closure – Taking the Proper Turn at a Thermodynamic Crossing

“…During the reaction, 1‐phosphaallylic anion ( E )‐7 a is formed as an intermediate and its 31 P NMR chemical shift at 12.4 ppm is comparable to literature known phosphaallylic anions by Niecke et al. [13] Similarly, alkynyl vinylphosphanes 10 b , 10 b’ and 10 c upon deprotonation convert via phosphaallylic anions into the corresponding phosphetes 3 b , 3 b’ and 3 c at room temperature as well. The transition states of the ring closures were calculated in the presence of one EtOH molecule (see Figure S3).…”

A Li10 Cage Containing the [C6H11P⋅⋅⋅–C(Ph)⋅⋅⋅–N]2− Ion: Umpolung in the Oligomerization of a Nitrile

“…cyclo-tBu 4 Sb 4 [7] proved to be a versatile reagent in the synthesis of complexes containing both Sb 2 and cyclo-Sb 3 ligands. cyclo-tBu 4 Sb 4 [7] proved to be a versatile reagent in the synthesis of complexes containing both Sb 2 and cyclo-Sb 3 ligands.…”

“…Similar competition is well known in reactions of ketones with Grignard reagents, [4] and the reactions of Ph 2 CO with a range of lithium amides occur through the [Ph 2 C . [6] The room-temperature 31 P NMR spectrum of the initial mixture of PhCN and as high as 65.2 in similarly substituted 1-phosphallyl anions [7] ). [5] A further clue to the participation of radicals in the reaction forming 1 is the rapid development of a sustained (> 2 h), deep green color upon addition of nBuLi to the mixture of PhCN and CyPHLi.…”

The 1-Phosphaallyl Anion as a Versatile Building Block in Reactions with Alkynes and Fischer-Type Alkynyltungsten Carbene Complexes

“…Silica gel (Merck, 0.063−0.200 mm) was degassed in a high vacuum and stored under argon. 1,2,3-Triphenyl-1-phosphaallyllithium, 1,2,3,4,5-pentaphenyl-2,3-dihydrophosphole,3a pentacarbonyl[(phenylethynyl)( N -pyrrolidino)carbene]tungsten(0) and pentacarbonyl[((p-tolyl)ethynyl)(methoxy)carbene]tungsten(0) were prepared according to procedures described in the literature. All chemical shifts are reported in parts per million.…”

“…The anionic 1,3-cycloaddition reaction has been widely used for the synthesis of nitrogen containing heterocycles . We recently reported on a reaction of the (1-phosphaallyl)lithium species Li(dme) 3 [PhP−CPhC(Ph)H] ( 1 ) and diphenylacetylene which generated a lithium dihydrophospholide, providing the first example of a structurally characterized uncoordinated allyl anion 2 . Subsequent protonation by the mild carbon acid phenylacetylene yielded the 2,3-dihydrophosphole 3 (Scheme ).…”