Synthesis of N-acyl-, N-sulfonyl-, and N-phosphinylphospha(PV)azenes by a redox-condensation reaction using amides, triphenylphosphine, and diethyl azodicarboxylate

Synthesis, Structure, Reactivity, and Catalytic Activity of C,N‐ and C,N,N‐Orthopalladated Iminophosphoranes

“…The IR spectra of 11 and 12 show sharp absorptions due to the ν CO stretch at 1644 (11) and 1646 (12) cm -1 , shifted to higher frequencies with respect to the corresponding absorption in the free ligand, and also show two strong bands due to the ν PN stretch at 1332 (11) and 1330 (12) cm -1 , while in the free ligand this absorption appears at 1366 cm -1 . [46] These two facts indicate that the iminic Natom is coordinated to the metal centre. [30] The 1 H NMR spectra of 11 and 12 show similar patterns, and unambiguously reveal the presence of the cyclometallated [M(C 6 H 4 -2-PPh 2 =N-)] unit.…”

“…The reactivity of different iminophosphoranes, such as Ph 3 P=NPh, Ph 3 P=NCN, [45] Ph 3 P=NC(O)CH 2 Cl, Ph 3 P=NC(O)-2-NC 5 H 4 [46] and Ph 3 P=N-NϵC [47] towards some standard metallating Pd II and Pt II reagents has been studied. The reaction of Pd(OAc) 2 (OAc = acetate) with Ph 3 P=NPh (1:1 molar ratio) in refluxing CH 2 Cl 2 , followed by evaporation to dryness and treatment of the residue with excess LiCl in MeOH, gives the orthometallated dimer [Pd(C 6 H 4 -2-PPh 2 =NPh-κ-C,N)(μ-Cl)] 2 (1) in very good yield (see Scheme 1).…”

“…Thus, four different signals assigned to the protons of the C 6 H 4 unit can be observed at δ = 7.00, 7.13, 7.28 and 8.10 ppm in complex 11 and at δ = 6.95, 7.05, 7.23 and 8.02 ppm in 12, with the signal at δ = 8.02 ppm showing 195 Pt satellites, as well as signals corresponding to the pyridine group. Moreover, the N-bonding of the pyridine ring can be inferred from the shift to low field of the resonance attributed to the H α proton (δ = 8.97 ppm in 11; δ = 9.17 ppm in 12) with respect to its position in the free ligand (δ = 8.69 ppm), [46] and from the presence, in 12, of 195 Pt satellites for the multiplet at δ = 9.17 ppm ( 3 J Pt,H Ϸ 20 Hz). These IR and 1 H NMR spectroscopic data are in good agreement with the structure proposed in Scheme 2 for 11 and 12, in which the orthometallated iminophosphorane acts as a C,N,N-terdentate ligand.…”

Facile and Stereoselective Synthesis of Non-Racemic 3,3,3-Trifluoroalanine

“…> 95%) [10a-d] (Scheme 1) was synthesized by reaction of the Davis sulfinamide (S) -1 [11] with DEAD/PPh 3 (92%) [12]. Next, a high yielding Staudinger (azaWittig) reaction of (S)-2 with ethyl trifluoropyruvate was performed in benzene freshly distilled from Na (ca.…”

Synthesis of Nonracemic α-Trifluoromethyl α-Amino Acids from Sulfinimines of Trifluoropyruvate

“…Key: i) (Me 3 Si) 2 NLi, THF; ii) CF 3 COCOOEt However, it proved possible to prepare the key sulfinimines (S)-1a and (S)-1b efficiently by a different pathway; namely by Staudinger (aza-Wittig) reaction, [18] which is known to be an extremely useful tool for preparing imines with a strongly electrophilic character (Scheme 4). Thus, the p-tolylsulfinamide (S)-7, easily obtained as described by Davis, [16] was treated with PPh 3 /DEAD in dry THF at room temp., [19] affording in good yield (92%) the chiral Staudinger reagent (S)-8, formerly obtained only in racemic form and with low yields from Ph 3 PϭNH, p-Tol-SOCl, and triethylamine. [20] Enantiomeric (R)-8 was obtained from (R)-7 in identical fashion.…”