Imino-phosphine

A new class of metaphosphinates, namely iminomethylenephosphoranes (1 with R = N(SiMe3)2, X = NSiMe3) is accessible by reaction of diazoalkanes with imino-phosphines (SiMe3)2N—P=N—SiMe3. Depending on the substituents on the methylene carbon atom, compounds of this class are either stable or dimerize across the P=C or P=N double bond 141). 

Wirringa et al. obtained an unusual l,3-diaza-2-phosphaallyl(methylzinc) complex (Figure 44, 85), featuring a two-coordinate phosphorus atom, from the deprotonation of a bulky amino(imino)phosphine with dimethylzinc.144... 

XRD analysis of l,l,l,3,3,3-hexafluoro-2-propanyloxy-(2,4,6-tri-t-butylphenyl-imino)phosphine (57) revealed a P=N bond-length of 1.526 A, the shortest ever observed in trans (E)-iminophosphines. X-Ray structural analysis of the diphosphene DmpP=PDmp,where Dmp = 2,6-dimesitylphenyl-, also revealed a trans configuration (about P=P) and a short P=P bond-length of 1.985 The... 

Other catalytic systems were used recently, namely a Ddppi system (67, Scheme 8.14) for dicyclopentadiene and di(methylcyclopentadiene) [96] and imino-phosphine complexes (Scheme 8.19, 97 and 98) or hybrid terdentate carbene hgand complexes (99) [133] for norbornene. Furtlierrnore, the copolymerization of various substituted norbomadienes and norbomenes has been achieved with Rh6(CO)i6 under water gas shift reaction conditions (55 ""C, water and 100 atm CO) [134],... 

Chiral ferrocenyl-imino phosphines as ligands for palladium-catalysed... 

CHIRAL FERROCENYL-IMINO PHOSPHINES AS LIGANDS FOR PALLADIUM-CATALYSED ENANTIOSELECTIVE ALLYLIC ALKYLATIONS... 

The cationic Pd(II)-7i-allyl complexes of the formula [(Ligand)Pd(ri3-C3H5)]PF6 (Ligand = ferrocenyl imino-phosphine la-e) were isolated in the solid state by the literature procedure15,61 using [(ri3-C3H5)PdCl]2 as starting material.[7] The complexes obtained were used as catalyst precursors for the asymmetric allylic... 

A catalytic Aza-Wittig reaction was developed for the synthesis of 4-3//-quinazolinones, involving formation of the corresponding imino-phosphine intermediate in the first step (Scheme 63). ... 

To a solution of imine 2 (5) (18.8 g, 69.8 mmol) in THF (70 mL), n-BuLi (43.7 mL, 69.9 mmol) is added dropwise at -80°C. The reaction mixture is allowed to warm to room temperature, and then stirred for 30 min. After cooling the mixture down to -80 °C, a solution of chlorophosphine 1 (18.6 g, 69.8 mmol) in THF (40 mL) is added slowly, and the mixture is allowed to warm to room temperature. After 1 h of stirring, all volatiles are removed under vacuum, and the residue is extracted with pentane (200 mL) and toluene (200 mL). Once the solvent evaporated, the residue is washed with acetonitrile (50 mL x 3). The solid is then dried under vacuum, and the imino-phosphine 3 is obtained as a white powder. Yield 35.0 g, (98%). 

This synthetic method can be used for the preparation of a variety of imino-phosphines, just by changing, either the aryl substituent or the chlorophosphine. 

A series of new organogermanium imino phosphines has been reported in the literature. Two new synthetic routes (l) and (ill) leading to imino phosphines are used as shown in the following scheme. 

---