Romanov-Michailidis, Fedor’s team published research in Angewandte Chemie, International Edition in 52 | CAS: 929294-27-9

Angewandte Chemie, International Edition published new progress about 929294-27-9. 929294-27-9 belongs to chiral-phosphine-ligands, auxiliary class Chiral Phosphoric Acids, name is R-3,3′-Bis(2,4,6-triisopropylphenyl)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl-2,2′-diyl hydrogenphosphate, and the molecular formula is C50H65O4P, Formula: C50H65O4P.

Romanov-Michailidis, Fedor published the artcileEnantioselective Organocatalytic Fluorination-Induced Wagner-Meerwein Rearrangement, Formula: C50H65O4P, the publication is Angewandte Chemie, International Edition (2013), 52(35), 9266-9270, database is CAplus and MEDLINE.

The synthesis of the target compounds was achieved (optimized conditions) using 1-(chloromethyl)-4-fluoro-1,4-diazoniabicyclo[2.2.2]octane tetrafluoroborate(1-) (Selectfluor) as fluorination agent and a chiral dinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepin 4-oxide as catalyst. The title compounds thus formed included 3′,4′-dihydro-2′-(fluoro)spiro[cyclopentane-1,1′(2′H)-naphthalen]-2-one derivatives, 3′,4′-dihydro-2′-(fluoro)spiro[cyclobutane-1,1′(2′H)-naphthalen]-2-one derivatives and 3′,4′-dihydro-2′-(fluoro)spiro[cyclohexane-1,1′(2′H)-naphthalen]-2-one derivatives The title compounds thus formed included a chiral spiro[cyclobutane-naphthalenone] derivative (I). Reactants included 1-(3,4-dihydro-1-naphthalenyl)cyclobutanol, 1-(2H-1-benzopyran-4-yl)cyclobutanol, 1-(3,4-dihydro-1-naphthalenyl)cyclopentanol 1-(3,4-dihydro-1-naphthalenyl)cyclopropanol etc.

Angewandte Chemie, International Edition published new progress about 929294-27-9. 929294-27-9 belongs to chiral-phosphine-ligands, auxiliary class Chiral Phosphoric Acids, name is R-3,3′-Bis(2,4,6-triisopropylphenyl)-5,5′,6,6′,7,7′,8,8′-octahydro-1,1′-binaphthyl-2,2′-diyl hydrogenphosphate, and the molecular formula is C50H65O4P, Formula: C50H65O4P.

Referemce:
https://en.wikipedia.org/wiki/Phosphine_ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Hrdina, Radim’s team published research in Organometallics in 32 | CAS: 297752-25-1

Organometallics published new progress about 297752-25-1. 297752-25-1 belongs to chiral-phosphine-ligands, auxiliary class Chiral Phosphoric Acids, name is (R)-4-Hydroxy-8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, and the molecular formula is C20H21O4P, Formula: C20H21O4P.

Hrdina, Radim published the artcileSynthesis, Structural Analysis, and Catalytic Properties of Tetrakis(binaphthyl or octahydrobinaphthyl phosphate) Dirhodium(II,II) Complexes, Formula: C20H21O4P, the publication is Organometallics (2013), 32(2), 473-479, database is CAplus.

The x-ray structural analyses of homoleptic Rh(II) complexes made of enantiopure (R)-1,1′-binaphthyl and (R)-(5,5′,6,6′,7,7′,8,8′-octahydro)binaphthyl phosphate ligands are for the 1st time presented. The possibility to introduce halogen atoms at the 3,3′-positions is also reported. The isolated dirhodium complexes were further tested as catalysts (1 mol %) in enantioselective cyclopropanations and Si-H insertion reactions, affording chiral cyclopropanes and silanes in good yield but moderate enantioselectivity (ee maximum 63%).

Organometallics published new progress about 297752-25-1. 297752-25-1 belongs to chiral-phosphine-ligands, auxiliary class Chiral Phosphoric Acids, name is (R)-4-Hydroxy-8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, and the molecular formula is C20H21O4P, Formula: C20H21O4P.

Referemce:
https://en.wikipedia.org/wiki/Phosphine_ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Cheng, Ke’s team published research in Chinese Journal of Chemistry in 29 | CAS: 297752-25-1

Chinese Journal of Chemistry published new progress about 297752-25-1. 297752-25-1 belongs to chiral-phosphine-ligands, auxiliary class Chiral Phosphoric Acids, name is (R)-4-Hydroxy-8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, and the molecular formula is C20H21O4P, HPLC of Formula: 297752-25-1.

Cheng, Ke published the artcileChiral phosphoric acid catalyzed enantioselective allylation of aldehydes with allyltrichlorosilane, HPLC of Formula: 297752-25-1, the publication is Chinese Journal of Chemistry (2011), 29(8), 1669-1671, database is CAplus.

Easily accessible chiral phosphoric acid 1b has been applied as efficient organocatalyst for the asym. allylation of aldehydes with allyltrichlorosilane. In the presence of 20 mol% of 1b, the allylation of a broad range of aldehydes proceeded smoothly to give the corresponding homoallylic alc. with up to 87% ee and 97% yield.

Chinese Journal of Chemistry published new progress about 297752-25-1. 297752-25-1 belongs to chiral-phosphine-ligands, auxiliary class Chiral Phosphoric Acids, name is (R)-4-Hydroxy-8,9,10,11,12,13,14,15-octahydrodinaphtho[2,1-d:1′,2′-f][1,3,2]dioxaphosphepine 4-oxide, and the molecular formula is C20H21O4P, HPLC of Formula: 297752-25-1.

Referemce:
https://en.wikipedia.org/wiki/Phosphine_ligand,
Chiral phosphine ligands in asymmetric synthesis. Molecular structure and absolute configuration of (1,5-cyclooctadiene)-(2S,3S)-2,3-bis(diphenylphosphino)butanerhodium(I) perchlorate tetrahydrofuran solvate

Ma, Yu’s team published research in Chirality in 2019 | CAS: 210169-54-3

(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) is a chelating ligand used to prepare coordination complex catalysts, such as its use in Pd catalysts for the enantioselective synthesis of spiro- or benzofused hetereocycles with exocyclic olefins via enantioselective intramolecular dearomative Heck reaction of indoles, benzofurans, pyrroles and furans.Related Products of 210169-54-3

The author of 《Enantioselective liquid-liquid extraction of DL-mandelic acid using chiral diphosphine ligands as extractants》 were Ma, Yu; Liu, Xiong; Zhou, Wenqi; Cao, Ting. And the article was published in Chirality in 2019. Related Products of 210169-54-3 The author mentioned the following in the article:

In order to expand the application range of chiral diphosphine ligands, (S)-BINAP, (S)-SEGPHOS, and (S)-MeO-BIPHEP were employed as extractants to recognize DL-mandelic acid. The results indicated that (S)-SEGPHOS-Cu exhibited considerable ability to recognize DL-mandelic acid with operational enantioselectivity (α) of 2.677. The process of extraction of DL-mandelic acid using (S)-SEGPHOS-Cu as extractant was systematically investigated. Performance factor (pf) was adopted to comprehensively evaluate the extraction After optimization by response surface methodol. (RSM), the optimal extraction condition is temperature of 5.5°C, (S)-SEGPHOS-Cu concentration of 3.0 mmol/L, and pH of 8.0. And the predicted and exptl. maximum values of pf were 0.26374 and 0.26839, resp. After reading the article, we found that the author used (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3Related Products of 210169-54-3)

(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) is a chelating ligand used to prepare coordination complex catalysts, such as its use in Pd catalysts for the enantioselective synthesis of spiro- or benzofused hetereocycles with exocyclic olefins via enantioselective intramolecular dearomative Heck reaction of indoles, benzofurans, pyrroles and furans.Related Products of 210169-54-3

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Wei, Xiao-Feng’s team published research in Chem in 2019 | CAS: 849924-49-8

(R)-1-{(R)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}-ethylbis(2-methylphenyl)phosphine(cas: 849924-49-8) belongs to chiral phosphine ligands. Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates. Quality Control of (R)-1-{(R)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}-ethylbis(2-methylphenyl)phosphine These intermediates are formed through nucleophilic attack of the phosphine catalysts at electron-poor nuclei (normally carbon atoms) and then proceed through several steps to form new chemical bonds.

Quality Control of (R)-1-{(R)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}-ethylbis(2-methylphenyl)phosphineOn March 14, 2019, Wei, Xiao-Feng; Wakaki, Takayuki; Itoh, Taisuke; Li, Hong-Liang; Yoshimura, Takayoshi; Miyazaki, Aya; Oisaki, Kounosuke; Hatanaka, Miho; Shimizu, Yohei; Kanai, Motomu published an article in Chem. The article was 《Catalytic Regio- and Enantioselective Proton Migration from Skipped Enynes to Allenes》. The article mentions the following:

Here, a copper(I)-catalyzed enantioselective proton migration from skipped enynes to allenes I [R1 = Ph, 3-MeC6H4, 3-thienyl, etc.; R2 = H, Me, Bn, etc.] as an efficient approach in chiral allene synthesis was reported. With catalyst loading as low as 0.5 mol %, the reaction proceeded smoothly under mild conditions without the need for addnl. stoichiometric reagents or generation of waste. Novel chiral ligand containing diphenylphosphine moiety plays a critical role in furnishing high catalyst activity, promoting regioselective protonation to produce allenes instead of conjugated enynes and inducing axial chirality of allenes. The multiple roles of the chiral ligand were rationalized by d. functional theory calculations In the experimental materials used by the author, we found (R)-1-{(R)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}-ethylbis(2-methylphenyl)phosphine(cas: 849924-49-8Quality Control of (R)-1-{(R)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}-ethylbis(2-methylphenyl)phosphine)

(R)-1-{(R)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}-ethylbis(2-methylphenyl)phosphine(cas: 849924-49-8) belongs to chiral phosphine ligands. Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates. Quality Control of (R)-1-{(R)-2-[Bis(4-methoxy-3,5-dimethylphenyl)phosphino]ferrocenyl}-ethylbis(2-methylphenyl)phosphine These intermediates are formed through nucleophilic attack of the phosphine catalysts at electron-poor nuclei (normally carbon atoms) and then proceed through several steps to form new chemical bonds.

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Li, Min’s team published research in RSC Advances in 2019 | CAS: 210169-54-3

(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) is a chelating ligand used to prepare coordination complex catalysts, such as its use in Pd catalysts for the enantioselective synthesis of spiro- or benzofused hetereocycles with exocyclic olefins via enantioselective intramolecular dearomative Heck reaction of indoles, benzofurans, pyrroles and furans.Electric Literature of C38H28O4P2

The author of 《Synthesis of N-aryl β-amino acid derivatives via Cu(II)-catalyzed asymmetric 1,4-reduction in air》 were Li, Min; Xia, Hong-Feng; Yang, Li-Yao; Hong, Tao; Xie, Lin-Jie; Li, Shijun; Wu, Jing. And the article was published in RSC Advances in 2019. Electric Literature of C38H28O4P2 The author mentioned the following in the article:

In the presence of the inexpensive and stable stoichiometric reductant polymethylhydrosiloxane (PMHS) as well as certain amounts of appropriate alc. and base additives, the non-precious metal copper-catalyzed asym. 1,4-hydrosilylation of β-aryl or β-alkyl-substituted N-aryl β-enamino esters was well realized to afford a diverse range of N-aryl β-amino acid esters in high yields and excellent enantioselectivities (26 examples, 90-98% ee). This approach tolerated the handling of both catalyst and reactants in air without special precautions. The chiral products obtained were successfully converted to the corresponding enantiomerically enriched β-lactam and unprotected β-amino acid ester, which highlighted the synthetic utility of the developed catalytic procedure. In the experimental materials used by the author, we found (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3Electric Literature of C38H28O4P2)

(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) is a chelating ligand used to prepare coordination complex catalysts, such as its use in Pd catalysts for the enantioselective synthesis of spiro- or benzofused hetereocycles with exocyclic olefins via enantioselective intramolecular dearomative Heck reaction of indoles, benzofurans, pyrroles and furans.Electric Literature of C38H28O4P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Kato, Minoru’s team published research in Synlett in 2009 | CAS: 1156547-61-3

(1S)-1-(Dicyclohexylphosphino)-2-[(R)-[2-(dicyclohexylphosphino)phenyl](dimethylamino)methyl]ferrocene(cas: 1156547-61-3) belongs to chiral phosphine ligands. Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates. SDS of cas: 1156547-61-3 These intermediates are formed through nucleophilic attack of the phosphine catalysts at electron-poor nuclei (normally carbon atoms) and then proceed through several steps to form new chemical bonds.

SDS of cas: 1156547-61-3On May 15, 2009 ,《Copper-ClickFerrophos-complex-catalyzed enantioselective reductive aldol reaction》 appeared in Synlett. The author of the article were Kato, Minoru; Oki, Hiroshi; Ogata, Kenichi; Fukuzawa, Shin-ichi. The article conveys some information:

Nonracemic ClickFerrophos (phosphinyltriazolylmethylferrocenylphosphine) ligands I (R = H, Ph; R1, R2 = Ph2P, Cy2P, dicyclopentylphosphinyl; Cy = cyclohexyl) are prepared as ligands for stereo- and enantioselective reductive aldol addition reactions of acrylates with aryl Me ketones and cyclohexanecarboxaldehyde. In the presence of I (R = Ph; R1 = R2 = Cy2P) and the methanol solvate of FCu(PPh3)3, acetophenones R3COMe (R3 = Ph, 4-FC6H4, 4-ClC6H4, 3-ClC6H4, 4-F3CC6H4, 4-MeOC6H4, 2-thienyl, 3-thienyl) undergo phenylsilane-mediated reductive aldol addition reactions with Me acrylate to give β-hydroxyesters II in 36-93% yields, 90:10-99:1 dr, and in 73-85% ee; the use of other silanes and ligand and the use of additives gives products with reduced diastereoselectivities or enantioselectivities. Phenylsilane-mediated reductive aldol additions of cyclohexanecarboxaldehyde and Me, tert-Bu, and cyclohexyl acrylate in the presence of nonracemic ClickFerrophos ligands give β-hydroxyesters in variable diastereoselectivities and enantioselectivities. In the experiment, the researchers used many compounds, for example, (1S)-1-(Dicyclohexylphosphino)-2-[(R)-[2-(dicyclohexylphosphino)phenyl](dimethylamino)methyl]ferrocene(cas: 1156547-61-3SDS of cas: 1156547-61-3)

(1S)-1-(Dicyclohexylphosphino)-2-[(R)-[2-(dicyclohexylphosphino)phenyl](dimethylamino)methyl]ferrocene(cas: 1156547-61-3) belongs to chiral phosphine ligands. Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates. SDS of cas: 1156547-61-3 These intermediates are formed through nucleophilic attack of the phosphine catalysts at electron-poor nuclei (normally carbon atoms) and then proceed through several steps to form new chemical bonds.

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Ji, Xiong’s team published research in Tetrahedron in 2017 | CAS: 286454-86-2

(S)-1-(Diphenylphosphino)-3,3-dimethylbutan-2-amine(cas:286454-86-2) is one of aminophosphine type ligands. An increased interest in aminophosphine type ligands used for asymmetric synthesis has been witnessed.HPLC of Formula: 286454-86-2 This growth in popularity of aminophosphine ligands in asymmetric synthesis is in part due to the growing number of convenient synthetic pathways leading to useful ligand sets.

HPLC of Formula: 286454-86-2On October 12, 2017 ,《Dual-reagent organophosphine catalyzed asymmetric Mannich reactions of isocyanoacetates with N-Boc-aldimines》 was published in Tetrahedron. The article was written by Ji, Xiong; Cao, Wei-Guo; Zhao, Gang. The article contains the following contents:

A combination of an amino-acid derived chiral phosphine catalyst and Me acrylate has been employed to catalyze the direct Mannich reaction of α-aryl isocyanoacetate and N-Boc-aldimines efficiently. The loading of the catalyst could be as low as 0.5 mol% without compromise on the yield and enantioselectivity and the corresponding chiral adducts I (R = Me, Bn, t-Bu, i-Pr; Ar1 = Ph, 3-MeC6H4, 3-MeOC6H4, 4-BrC6H4, etc.; Ar2 = 3-MeC6H4, 3-MeOC6H4, 4-BFC6H4, etc.) were obtained in excellent yields (up to 98%) and good enantioselectivities (up to 95%). The experimental part of the paper was very detailed, including the reaction process of (S)-1-(Diphenylphosphino)-3,3-dimethylbutan-2-amine(cas: 286454-86-2HPLC of Formula: 286454-86-2)

(S)-1-(Diphenylphosphino)-3,3-dimethylbutan-2-amine(cas:286454-86-2) is one of aminophosphine type ligands. An increased interest in aminophosphine type ligands used for asymmetric synthesis has been witnessed.HPLC of Formula: 286454-86-2 This growth in popularity of aminophosphine ligands in asymmetric synthesis is in part due to the growing number of convenient synthetic pathways leading to useful ligand sets.

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Xu, Qi’s team published research in Organic Letters in 2022 | CAS: 210169-54-3

(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) is a chelating ligand used to prepare coordination complex catalysts, such as its use in Pd catalysts for the enantioselective synthesis of spiro- or benzofused hetereocycles with exocyclic olefins via enantioselective intramolecular dearomative Heck reaction of indoles, benzofurans, pyrroles and furans.Product Details of 210169-54-3

In 2022,Xu, Qi; Zhang, Huan; Ge, Fang-Bei; Wang, Xiao-Mei; Zhang, Peng; Lu, Chuan-Jun; Liu, Ren-Rong published an article in Organic Letters. The title of the article was 《Cu(I)-Catalyzed Asymmetric Arylation of Pyrroles with Diaryliodonium Salts toward the Synthesis of N-N Atropisomers》.Product Details of 210169-54-3 The author mentioned the following in the article:

The copper(I) catalysis using a bis(phosphine) dioxide ligand could catalyze the desym. C-H arylation of prochiral bipyrroles was reported. More than 50 nitrogen-nitrogen atropisomers I [R1 = Ph, 3-ClC6H4, 2-naphthyl, etc.; R2 = Me, Et, Bn, etc.; R3 = Me, Et, i-Pr; R4 = H, Me; R1R4 = CH=CH-CH=CH; Ar = Ph, 4-MeC6H4, 3-ClC6H4, etc.] were achieved in good to excellent yields with excellent enantioselectivities (≤97% yield, ≤98% ee). The reaction proceeded under mild conditions with good functional group compatibility on arenes and diaryliodonium salts. Moreover, this principle enabled iterative arylation of the bipyrroles to enantioselectively arylate different positions during the catalysis of copper. In addition to this study using (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole, there are many other studies that have used (S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3Product Details of 210169-54-3) was used in this study.

(S)-5,5′-Bis(diphenylphosphino)-4,4′-bi-1,3-benzodioxole(cas: 210169-54-3) is a chelating ligand used to prepare coordination complex catalysts, such as its use in Pd catalysts for the enantioselective synthesis of spiro- or benzofused hetereocycles with exocyclic olefins via enantioselective intramolecular dearomative Heck reaction of indoles, benzofurans, pyrroles and furans.Product Details of 210169-54-3

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Chen, Peng’s team published research in Tetrahedron in 2016 | CAS: 286454-86-2

(S)-1-(Diphenylphosphino)-3,3-dimethylbutan-2-amine(cas:286454-86-2) is one of aminophosphine type ligands. An increased interest in aminophosphine type ligands used for asymmetric synthesis has been witnessed.Application of 286454-86-2 This growth in popularity of aminophosphine ligands in asymmetric synthesis is in part due to the growing number of convenient synthetic pathways leading to useful ligand sets.

Application of 286454-86-2On May 26, 2016, Chen, Peng; Su, Xiao; Zhou, Wei; Xiao, Yuanjing; Zhang, Junliang published an article in Tetrahedron. The article was 《Novel chiral sulfinamide phosphines: valuable precursors to chiral β-aminophosphines》. The article mentions the following:

Starting from com. available aldehyde and chiral tert-butanesulfinamide, chiral sulfinamide phosphines Ph2PCH2CH(R)NHS(:O)But (Xiao-Phos, R = alkyl, aryl, hetaryl) were synthesized via a two-step condensation-nucleophilic addition procedure. In most cases, nucleophilic addition of the N-tert-butanesulfinyl imine with [(diphenylphosphino)methyl]lithium (Ph2PCH2Li) showed high diastereoselectivity (d.r > 20:1) with BF3 as additives. Following removal of the chiral auxiliary, an important class of ligands i.e. chiral β-aminophosphines and its derivatives were obtained in high yields using this approach. The experimental part of the paper was very detailed, including the reaction process of (S)-1-(Diphenylphosphino)-3,3-dimethylbutan-2-amine(cas: 286454-86-2Application of 286454-86-2)

(S)-1-(Diphenylphosphino)-3,3-dimethylbutan-2-amine(cas:286454-86-2) is one of aminophosphine type ligands. An increased interest in aminophosphine type ligands used for asymmetric synthesis has been witnessed.Application of 286454-86-2 This growth in popularity of aminophosphine ligands in asymmetric synthesis is in part due to the growing number of convenient synthetic pathways leading to useful ligand sets.

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis