Bis aminophosphine

Although the vast majority of centrally chiral diphosphine ligands to be employed in enantioselective rhodium-catalyzed hydroborations possess -symmetry, there are a few examples of ( -symmetric diphosphine ligands. Buono prepared bis(aminophosphine) ligands 35-38,81 while Bianchini reported (R, i )-BDPBzP 39 (Figure 5).82... 

In an ESI-MS monitoring study of the Suzuki-Miyaura reaction using a dichloro-bis(aminophosphine) palladium precatalyst, binuclear Pd complexes were detected after the reaction went to completion, indicating a catalyst sink or a resting state. Addition of starting reagents resumes the reaction, suggesting the active role of the binuclear complex as a reservoir of mononuclear active catalyst. Other interpretations propose the involvement of Pd nanoparticles in which binuclear Pd complexes act as a precursor or perhaps even the active catalyst, but the last possibility seems unlikely. A mechanism for this transformation was proposed based on the intercepted species (Scheme 10) [62]. 

Of particular interest in the latter case is the use of N-NMR spectroscopy for the determination of J( P, N) data, of which there are few examples for systems having two coordinate sp -hybridised nitrogen linked to phosphorus. " Various acyclic bis(aminophosphines) have also been reported, including the imino-functional system (96), the bis(phosphino)-hydrazines (97) and -ureas (98), and the l,8-bis[bis(dialkylamino)phosphino]naphthalenes (99). There has also been significant activity in the synthesis of cyclic aminophosphines. An improved route to the four-membered ring system (100) is afforded by the reaction of phosphorus trichloride with t-butylamine in a 1 3 mole ratio in THF. Treatment of this with ammonia in THF/triethylamine at — 78°C gives (101),... 

Brunei, J.-M., Buono, G. Enantioselective rhodium catalyzed hydroboration of olefins using chiral bis(aminophosphine) ligands. Tetrahedron Lett. 1999, 40, 3561-3564. 

Aminophosphines. - The bis(V-pyrrolidinyl)phosphines (139), prepared conventionally by treatment of the appropriate organodichlorophosphine with an excess of pyrrolidine, have proved to be unusually electron-rich <7-donor ligands when compared to either tris(V-pyrrolidinyl)phosphine, or trialkyl-and triaryl-phosphines. Full details of a route to the polycylic aminophos-phirane systems (140) have now appeared. The bis(aminophosphine) (141) has been prepared and used in the synthesis of macrocyclic metal complexes. Two new chiral aminophosphine systems (142) and (143) have been prepared by transamidation of related aryl bis(dimethylamino)phosphines with a chiral amine. The chiral aminophosphine (144) has been obtained from the reaction of chlorodiphenylphosphine with the methyl ester of alanine. A range of ether-functionalised aminophosphines (145) has also been prepared. 

Very recently, Wang has prepared a new class of bis (aminophosphine) ligands 38 based on a new biphenyldiamine 4,4, 6,6 tetrakis trifluoromethyl biphenyl 2,2 diamine (TF BIPHAM) (Figure 9.8) [41]. These bis(aminophosphine) ligands ex hibited excellent to almost perfect enantioselectivities in the Rh catalyzed asymmet ric hydrogenation of enamides (97.6 99.9% ee) even at a catalyst loading ofO.l mol%. 

Various alkylene-bis(aminophosphines) (42) and (43) have been synthesized and (42 = 4) characterized by its reactions with chalcogenides, BH3, BBrs, PCI3, MeOH, HgS, and 83. The bis-aminophosphines (44) and (45) have been prepared by standard methods and used for the preparation of the corresponding chlorophosphines (46). Other new synthons of related type are (47). Thus (47 X = NMe) has been used to prepare a series of 1-methyl-1,3-benzazaphos-pholes (48), and (48 R = H) could be lithiated at carbon with interesting possibilities for further substitution. The X-ray structures of (49) and (50), two products from the reaction of tris(diethylamino)phosphine with aniline, have been reported. ... 

The chemistry of cyclophosph(m)azanes has been reviewed. The cyclo-phosph(m)azane (51) or (52) is the main product from the reaction of phosphorus trichloride with ethylamine, depending on the stoicheiometry. Both (51) and (52) have been isolated and characterized. Further studies of the reactions of disilylated ureas with chlorophosphines have resulted in a new bicyclic bis-aminophosphine (53). Diazaphosphetidines (54), diazadiphosphetidines (55), and thiadiazaphosphetidines (56) have been prepared by exchange of diethyl-amino groups with the appropriate diamide. ... 

Displacements. Nickel complexes can serve as an alternative to the Pd catalysts, e.g., in the synthesis of allylamines and a-allylmalonic esters. A report on the latter reaction states that bis(aminophosphine) ligands are more efficient than dppb and other usual phosphines. 

Roucoux, A., Suisse, 1., Devocelle, M., Carpentier, J.F., Agboussou, F., Mortreux, A. (1996) Rh(I)-bis(aminophosphine)complexes as catalysts for asymmetric hydrogenation of activated ketones. Tetrahedron Asymm. 7, 379-382. 

This chapter will also deal with compounds containing two or three phosphinous amide units, which, for simpUcity, will be named here as bis(amino-phosphanes) or tris(aminophosphanes) but not with phosphinous amides containing other additional organophosphorus functionaUties as, for instance, the so-called aminophosphine phosphinites (AMMP), which have been the subject of increasing attention in the Uterature dealing with catalytic asymmetric transformations and have been treated in other reviews [2,3]. 

Other chiral ligands such as BINAP (where BINAP is bis(diarylphosphino)-1,1 binaphthyl) or aminophosphines are also efficient for stereoselective synthesis of chiral-at-metal Ru complexes [39-41]. 

The bidentate phosphine dppe (l,2-bis(diphenylphosphino)ethane) and the aminophosphine eddp (2-aminoethyl-diphenylphosphine) form mixed ligand (N, P, O) complexes such as Co(acac) (edpp)2 and Co(acac)(en)(dppe). A preference for trans N-Co-P and P-Co-P configurations over N-Co-N was found for the bis(edpp) complexes.925... 

Some data are also available on the effect of the structure of the phosphine or diphosphine on the optical yield in the asymmetric hydrocarbalkoxylation of 2-phenyl-1-propene (24) (see Table III). The best optical yield was obtained using 2,2-dimethyl-4,5-bis(dibenzo-phosphol-5-ylmethyl)-l,3-dioxolane as the chiral ligand. Much lower optical yields were obtained using aminophosphines or monophosphines. 

As illustrated in Fig. 6, imines serve as important intermediates for a number of solid-phase syntheses. Additional uses for these versatile intermediates are described in Fig. 9. Resin-bound thioketene acetals have been shown to condense with imines to provide, after reductive cleavage, a route to substituted aminoalcohols 6 [45], Aminophosphinic acids 7 were prepared by allowing bis(trimethylsilyl)phosphonite to react with resin-bound imines [46],... 

A 1,6-silyl migration from N to O was postulated in the reaction of N,N -bis(trimethyl-silyl)aminophosphine 333 with ethynyl methyl ketone 334 (equation 204)471. 

Substitution Compounds of Ni(CO)4 by Aminophosphines, Cyanato-phosphine, Thiocyanatophosphine. In the reaction of tetracarbonylnickel or bis(cyclopentadienylcarbonylnickel) with trisdimethylamino-phosphine(L), the disubstitution compound, Ni(CO)2L2, was obtained... 

Since Wymore and Bailar (1) first prepared trans-[CoX2 l,2-bis (diethylphosphino)ethane ]X (X = Cl-, Br , and I-) in I960, many cobalt(III)-phosphine complexes have been reported (2). However, no optically active cobalt(III)-phosphine complex has ever been prepared. This paper deals with the preparation, characterization and circular dichroism (CD) spectra of octahedral cobalt(III) complexes containing aminophosphines of the type,... 

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