Phosphine complexes, and

Triethylammonium formate is another reducing agent for q, /3-unsaturated carbonyl compounds. Pd on carbon is better catalyst than Pd-phosphine complex, and citral (49) is reduced to citronellal (50) smoothly[55]. However, the trisubstituted butenolide 60 is reduced to the saturated lactone with potassium formate using Pd(OAc)2. Triethylammonium formate is not effective. Enones are also reduced with potassium formate[56]. Sodium hypophosphite (61) is used for the reduction of double bonds catalyzed by Pd on charcoal[57]. 

A variety of methods have been reported for synthesizing platinum(O) tertiary phosphine complexes and a range of standard methods have been described in a series of reports in... 

Phosphine Complexes and Miscellaneous Complexes 9.10.4.3.1 Phosphine complexes... 

Y. Z. Yuan, A. P. Kozlova, K. Asakura, H. L. Wan, K. Tsai, and Y. Iwasawa, Supported Au catalysts prepared from Au phosphine complexes and As-precipitated metal hydroxides Characterization and low-temperature CO oxidation, J. Catal. 170(1), 191-199 (1997). 

Phosphazene polymers, 773-775 Phosphazenes, 769-773 Phosphine complexes, and oxides, 871... 

Reaction of (diisopropylamino)chloroboryl ethers of alkynols (57) with alkynyl-stannanes (58) in the presence of nickel catalysts has been reported to afford formal f/ms-alkynylboration products (60), which could undergo the Suzuki-Miyaura coupling with organic halides. The 2-borylalkenylnickel(II) complex (59) was isolated as an intermediate in a reaction of the chloroboryl ether (57) with 1 equiv. of a nickel(0)-phosphine complex and characterized by X-ray crystallography.61... 

Numerous phosphine complexes (and some arsine and stibine analogues) are known. With monophosphines these are mainly of the type (R3P) AgX, with rt = 1-4. The 1 1 complexes are tetrameric, with either cubane (18-I-II) or chair (18-I-III) structures depending on the steric requirements of both X and R3P Ag4I4(PPh3)4 undergoes cube-chair isomerization, and the two structural types may be obtained by crystallization from different solvents. 

Bis-pi-allyl Pd and Pt complexes have been found to catalyze the addition of allyl tributyltin to aldehydes [26]. These catalysts are formed in situ from Pd- and PtCl2-phosphine complexes and the allylstannanes (Fig. 7, step 1). The allylation step is depicted as a metallocene reaction of the aldehyde and an his-allylmetal complex (Fig. 7, step 3). The catalyst is regenerated by attack of the allylic stannane on the alcoholate-palladium complex formed in step 3. Representative additions of allyl and methallyl tributyltin to aldehydes with the pi-allyl platinum catalyst are summarized in Table 14. 

During the period documented by COMC(1995), dinuclear zirconocene(m) compounds were prepared using a variety of synthetic methods, including thermolysis of zirconocene(n) bis(phosphine) complexes and reduction of 2... 

A P- Al J-coupling constant for trimethylphosphine bound to the Lewis acid of Zeolite HY has been determined by Al to P INEPT methods,since coupling could not be resolved for this resonance (6= —49) in the P MAS NMR spectrum. The coupling was consistent with a five-coordinated aluminium Lewis acid/trimethyl phosphine complex, and thus a four-coordinated Lewis acid site. Bi- and tricyclic penta- and hexacoordinated-phosphoranes 25-28 have been... 

For a review on water-soluble phosphine complexes and their application in homogeneous catalysis, see N. Pinault and D. W. Bruce, Coord. Chem. Rev. 241, 1 (2003). 

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