Easily Accessible ChiralP,N-Bidentate Aryl Phosphites, Their Complexation and Application in Enantioselective Allylic Alkylation, Sulfonylation and Hydrosilylation

Abstract

New chiral P,N-hybrid aryl phosphites have been obtained by one-step phosphorylation of amino and imino alcohols. Complexation of the new ligands with [Rh(CO) 2 Cl] 2 , [Pd(COD)Cl 2 ] and [Pd(allyl)Cl] 2 was found to give chelate complexes [Rh(CO)Cl(η 2 -P ʝ N)], [PdCl 2 (η 2 -P ʝ N)] and [Pd-(allyl)(η 2 -P ʝ N)] + Cl − , respectively. With these new P,N-ligands, up to 82% ee enantioselectivity was achieved in the [a] The new P,N-bidentate aryl phosphites were synthesized by one-step phosphorylation of the corresponding amino and imino alcohols with bis(2,6-dimethylphenyl) chlorophosphite.They divide into two groups: ligands 3aϪ3f, possessing sp 3 -hybridized nitrogen atoms, and ligands 3gϪ3m, which have sp 2 -hybridized nitrogen atoms. All the compounds 3aϪm are soluble in conventional organic solvents and stable under dry conditions for several months. On treatment with [Rh(CO) 2 Cl] 2 , their neutral carbonyl(chloro)Rh I complexes were obtained.The ν(CO) and 1 J P,Rh parameters in their IR and 31 P NMR spectra act as sensitive indicators, which characterise the mode of complexation of the P,N-ligands and allow the π-acceptor ability of the phosphorus centre and the degree of electronic non-symmetry of the ligands to be estimated. [13Ϫ15] In general, ligands 3aϪ3m give chelate complexes. Thus, the

cis-1-Amino-2-indanol in Drug Design and Applications to Asymmetric Processes

“…The fact that the allylic alkylations could be performed at room temperature and did not necessitate lower reaction temperatures to achieve high selectivities is particularly noteworthy. These ligands were also tested in the allylic sulfonation reaction, and the same trends in enantioselectivities were observed 12 P,N-Bidentate aryl phosphite ligands. …”

cis-1-Amino-2-indanol in Drug Design and Applications to Asymmetric Processes

“…The fact that the allylic alkylations could be performed at room temperature and did not necessitate lower reaction temperatures to achieve high selectivities is particularly noteworthy. These ligands were also tested in the allylic sulfonation reaction, and the same trends in enantioselectivities were observed 12 P,N-Bidentate aryl phosphite ligands. …”

Cymantrene-based iminodiamidophosphites: the first phosphite-type ligands with planar chirality

“…This is not observed for complexes 8a, 9b and 10 either because of the fast interconversion of the isomers or due to the absence of one of the isomers. 22 It should be mentioned that compounds 8a and 8b, 9a and 9b and 10 are photosensitive. Thus, even a shortterm exposure to light of their chloroform solutions resulted in precipitation of a black solid and in the appearance of additional signals in the d P 110-130 and 7-33 ppm regions of their 31 P NMR spectra.…”

“…22 According to the 1 J(P, Rh) and m(CO) parameters of 6a and 6b and 7a and 7b, diamidophosphites 4a and 4b, and 5a and 5b occupy an intermediate position between phosphines and phosphoramidites in a spectrochemical range of organophosphorus ligands. 23,24 Besides, 4a and 4b, and 5a and 5b have practically identical p-acceptor and r-donor properties, for 1 J(P, Rh) and m(CO) parameters of their chlorocarbonyl rhodium complexes are rather close.…”

P,N-Bidentate aryl phosphite ligands based on chiral 2-imino-, 2-oxazolinyl and 2-oxazolidinyl phenols and their catalytic activity

“…The n(CO) and 1 J(P,Rh) parameters in the IR and 31 P NMR spectra act as sensitive indicators, which characterise the mode of complexation of the P,N-ligands and allow us to make a conclusion on the electronic properties of donor centres. 1,15,20 The values of n(CO) and 1 J(P,Rh) for compounds 6a,c,d and 7a,b clearly indicate the strong π-acceptor ability of phosphorus centres in ligands 3a,c,d and 5a,b and also show that all these ligands have similar electronic characteristics. 15,21,22 Two doublet signals in the 31 P NMR spectrum of 6a indicate the presence of two atropisomers of 6a, like in the case of oxazolinophosphite 3a.…”

“…1,15,20 The values of n(CO) and 1 J(P,Rh) for compounds 6a,c,d and 7a,b clearly indicate the strong π-acceptor ability of phosphorus centres in ligands 3a,c,d and 5a,b and also show that all these ligands have similar electronic characteristics. 15,21,22 Two doublet signals in the 31 P NMR spectrum of 6a indicate the presence of two atropisomers of 6a, like in the case of oxazolinophosphite 3a. In the 31 P NMR spectra of 7a,b, besides major peaks (Table 1), some additional signals are visible: d 114.6, 1 J(P,Rh) 298.4 Hz (10%) and d 113.4, 1 J(P,Rh) 302.9 Hz (15%) for 7a; d 122.9, 1 J(P,Rh) 283.6 Hz (25%) and d 110.6 Hz, 1 J(P,Rh) 300.1 Hz (37%) for 7b.…”

cis-1-Amino-2-indanol in Drug Design and Applications to Asymmetric Processes

“…The fact that the allylic alkylations could be performed at room temperature and did not necessitate lower reaction temperatures to achieve high selectivities is particularly noteworthy. These ligands were also tested in the allylic sulfonation reaction, and the same trends in enantioselectivities were observed 12 P,N-Bidentate aryl phosphite ligands. …”

Cymantrene-based iminodiamidophosphites: the first phosphite-type ligands with planar chirality

“…This is not observed for complexes 8a, 9b and 10 either because of the fast interconversion of the isomers or due to the absence of one of the isomers. 22 It should be mentioned that compounds 8a and 8b, 9a and 9b and 10 are photosensitive. Thus, even a shortterm exposure to light of their chloroform solutions resulted in precipitation of a black solid and in the appearance of additional signals in the d P 110-130 and 7-33 ppm regions of their 31 P NMR spectra.…”

“…22 According to the 1 J(P, Rh) and m(CO) parameters of 6a and 6b and 7a and 7b, diamidophosphites 4a and 4b, and 5a and 5b occupy an intermediate position between phosphines and phosphoramidites in a spectrochemical range of organophosphorus ligands. 23,24 Besides, 4a and 4b, and 5a and 5b have practically identical p-acceptor and r-donor properties, for 1 J(P, Rh) and m(CO) parameters of their chlorocarbonyl rhodium complexes are rather close.…”

P,N-Bidentate aryl phosphite ligands based on chiral 2-imino-, 2-oxazolinyl and 2-oxazolidinyl phenols and their catalytic activity

“…The n(CO) and 1 J(P,Rh) parameters in the IR and 31 P NMR spectra act as sensitive indicators, which characterise the mode of complexation of the P,N-ligands and allow us to make a conclusion on the electronic properties of donor centres. 1,15,20 The values of n(CO) and 1 J(P,Rh) for compounds 6a,c,d and 7a,b clearly indicate the strong π-acceptor ability of phosphorus centres in ligands 3a,c,d and 5a,b and also show that all these ligands have similar electronic characteristics. 15,21,22 Two doublet signals in the 31 P NMR spectrum of 6a indicate the presence of two atropisomers of 6a, like in the case of oxazolinophosphite 3a.…”

“…1,15,20 The values of n(CO) and 1 J(P,Rh) for compounds 6a,c,d and 7a,b clearly indicate the strong π-acceptor ability of phosphorus centres in ligands 3a,c,d and 5a,b and also show that all these ligands have similar electronic characteristics. 15,21,22 Two doublet signals in the 31 P NMR spectrum of 6a indicate the presence of two atropisomers of 6a, like in the case of oxazolinophosphite 3a. In the 31 P NMR spectra of 7a,b, besides major peaks (Table 1), some additional signals are visible: d 114.6, 1 J(P,Rh) 298.4 Hz (10%) and d 113.4, 1 J(P,Rh) 302.9 Hz (15%) for 7a; d 122.9, 1 J(P,Rh) 283.6 Hz (25%) and d 110.6 Hz, 1 J(P,Rh) 300.1 Hz (37%) for 7b.…”

cis-1-Amino-2-indanol in Drug Design and Applications to Asymmetric Processes

“…The fact that the allylic alkylations could be performed at room temperature and did not necessitate lower reaction temperatures to achieve high selectivities is particularly noteworthy. These ligands were also tested in the allylic sulfonation reaction, and the same trends in enantioselectivities were observed 12 P,N-Bidentate aryl phosphite ligands. …”

Cymantrene-based iminodiamidophosphites: the first phosphite-type ligands with planar chirality

“…This is not observed for complexes 8a, 9b and 10 either because of the fast interconversion of the isomers or due to the absence of one of the isomers. 22 It should be mentioned that compounds 8a and 8b, 9a and 9b and 10 are photosensitive. Thus, even a shortterm exposure to light of their chloroform solutions resulted in precipitation of a black solid and in the appearance of additional signals in the d P 110-130 and 7-33 ppm regions of their 31 P NMR spectra.…”

“…22 According to the 1 J(P, Rh) and m(CO) parameters of 6a and 6b and 7a and 7b, diamidophosphites 4a and 4b, and 5a and 5b occupy an intermediate position between phosphines and phosphoramidites in a spectrochemical range of organophosphorus ligands. 23,24 Besides, 4a and 4b, and 5a and 5b have practically identical p-acceptor and r-donor properties, for 1 J(P, Rh) and m(CO) parameters of their chlorocarbonyl rhodium complexes are rather close.…”

P,N-Bidentate aryl phosphite ligands based on chiral 2-imino-, 2-oxazolinyl and 2-oxazolidinyl phenols and their catalytic activity

“…The n(CO) and 1 J(P,Rh) parameters in the IR and 31 P NMR spectra act as sensitive indicators, which characterise the mode of complexation of the P,N-ligands and allow us to make a conclusion on the electronic properties of donor centres. 1,15,20 The values of n(CO) and 1 J(P,Rh) for compounds 6a,c,d and 7a,b clearly indicate the strong π-acceptor ability of phosphorus centres in ligands 3a,c,d and 5a,b and also show that all these ligands have similar electronic characteristics. 15,21,22 Two doublet signals in the 31 P NMR spectrum of 6a indicate the presence of two atropisomers of 6a, like in the case of oxazolinophosphite 3a.…”

“…1,15,20 The values of n(CO) and 1 J(P,Rh) for compounds 6a,c,d and 7a,b clearly indicate the strong π-acceptor ability of phosphorus centres in ligands 3a,c,d and 5a,b and also show that all these ligands have similar electronic characteristics. 15,21,22 Two doublet signals in the 31 P NMR spectrum of 6a indicate the presence of two atropisomers of 6a, like in the case of oxazolinophosphite 3a. In the 31 P NMR spectra of 7a,b, besides major peaks (Table 1), some additional signals are visible: d 114.6, 1 J(P,Rh) 298.4 Hz (10%) and d 113.4, 1 J(P,Rh) 302.9 Hz (15%) for 7a; d 122.9, 1 J(P,Rh) 283.6 Hz (25%) and d 110.6 Hz, 1 J(P,Rh) 300.1 Hz (37%) for 7b.…”