Tag: 790.8655

Enantioselective synthesis of tertiary α-hydroxyketones from unfunctionalized ketones: palladium-catalyzed asymmetric allylic alkylation of enolates was written by Trost, Barry M.;Koller, Raffael;Schaeffner, Benjamin. And the article was included in Angewandte Chemie, International Edition in 2012.Recommanded Product: N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) This article mentions the following:

A highly regio- and enantioselective palladium-catalyzed decarboxylative allylic alkylation to access functionalized tertiary α-hydroxyketones from ketones is introduced. Starting from tetralone derivatives and benzosuberone, through O-acylation with allyl imidazolecarboxylates followed by epoxidation with m-CPBA, rearrangement by treatment with BF₃·OEt₂, enolationprotection, and palladium-catalyzed asym. allylic alkylation, a series of α-hydroxy benzocyclic ketone derivatives were obtained in good yields and excellent stereoselectivities. Finally, the corresponding α-hydroxy benzocyclic ketones could be generated by romoving the methoxymethyl (MOM) or benzyloxymethyl (BOM) protecting group. In the experiment, the researchers used many compounds, for example, N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4Recommanded Product: N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide)).

N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4) belongs to chiral phosphine ligands. Phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000.Recommanded Product: N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide)

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Geminal Dicarboxylates as Carbonyl Surrogates for Asymmetric Synthesis. Part I. Asymmetric Addition of Malonate Nucleophiles was written by Trost, Barry M.;Lee, Chul Bom. And the article was included in Journal of the American Chemical Society in 2001.HPLC of Formula: 174810-09-4 This article mentions the following:

Asym. alkylations of allylic geminal dicarboxylates with dialkyl malonates have been investigated. The requisite allylic geminal dicarboxylates are prepared in good yields and high isomeric purities either by ferric chloride-catalyzed addition of acid anhydrides to α,β-unsaturated aldehydes or by palladium-catalyzed isomerization and addition reactions of propargylic acetates with acetic acid. E.g., treatment of trans-cinnamaldehyde with 5 equivalent in the presence of 0.5% iron (III) chloride gave (E)-PhCH:CHCH(OAc)₂ in 85% yield. E.g., treatment of (S)-MeCH[OSi(Ph)₂CMe₃]CCCH₂OAc with 1.2 equivalent acetic acid and 1 mol% tetrakis(triphenylphosphine)palladium in toluene at 110° gave (E,S)-MeCH[OSi(Ph)₂CMe₃]CH:CCHCH(OAc)₂ in 81% yield. The complex of di(allylchloropalladium) and nonracemic ligands derived from di(2-diphenylphosphinobenzoyl) amides of trans-1,2-diaminocyclohexane most efficiently catalyzed the asym. process to provide allylic carboxylate esters with high ee. E.g., sodium hydride was added to a solution of di-Me 2-methylmalonate and the mixture stirred at ambient temperature until gas evolution ceased; di(allylpalladium chloride), the (R,R)-trans-1,2-diaminocyclohexane di(2-diphenylphosphinobenzoyl) amide, and (E)-PhCH:CHCH(OAc)₂ were added and the mixture was stirred for 2 h to give (R,E)-PhCH:CHCH(OAc)C(Me)(CO₂Me)₂ in 92% yield as a single regioisomer in >95% ee. By systematic optimization studies, factors affecting the enantioselectivity of the reaction have been probed. In general, higher ee’s have been achieved with those conditions which facilitate kinetic capture of the incipient π-allylpalladium intermediate. These conditions also proved effective for achieving high regioselectivities. The minor regioisomeric product was formed when reactive substrates or achiral ligands were employed for the reaction, and could be minimized through the use of the chiral ligand. Under the established conditions, the alkylation of various gem-dicarboxylates afforded monoalkylated products in high yields with greater than 90% ee. The process constitutes the equivalent of an addition of a stabilized nucleophile to a carbonyl group with high asym. induction. In the experiment, the researchers used many compounds, for example, N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4HPLC of Formula: 174810-09-4).

N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4) belongs to chiral phosphine ligands. The synthesis of novel trialkylphosphines can be quite difficult, thereby limiting the scope of their chiral variants. Indeed, very little research on chiral tertiary phosphine-catalyzed asymmetric reactions occurred prior to the year 2000.HPLC of Formula: 174810-09-4

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Cyclic 1,2-Diketones as Core Building Blocks: A Strategy for the Total Synthesis of (-)-Terpestacin was written by Trost, Barry M.;Dong, Guangbin;Vance, Jennifer A.. And the article was included in Chemistry – A European Journal in 2010.Computed Properties of C52H44N2O2P2 This article mentions the following:

The sesterterpene (-)-terpestacin I is prepared using the stereoselective and enantioselective O-alkylation of diosphenols with allylic epoxides in the presence of a nonracemic diphosphine palladium catalyst and the subsequent stereoselective Claisen rearrangement to a nonracemic diosphenol with a quaternary stereocenter as the key steps. For example, reaction of 2-hydroxy-3-methyl-2-cyclopenten-1-one with 2-vinyl-2-methyloxirane (isoprene oxide) in the presence of tris(dibenzylideneacetone)dipalladium chloroform solvate and nonracemic Trost ligand II and tetrabutylammonium chloride followed by silylation yields the nonracemic tertiary allylic enol ether III (TIPS = triisopropylsilyl) in 93-95% yield and 88-96% ee; thermal rearrangement of III in chloroform (with adventitious HCl presumably as a catalyst) yields the substituted nonracemic diosphenol IV in 82-93% yield with 4-5:1 E:Z stereoselectivity. The palladium-catalyzed asym. allylic alkylation reaction of an allylic carbonate is used to generate the pendant hydroxypropyl moiety of I. Using this methodol., I is prepared in 20 steps (longest linear sequence) from com. available 2-hydroxy-3-methyl-2-cyclopenten-1-one. In the experiment, the researchers used many compounds, for example, N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4Computed Properties of C52H44N2O2P2).

N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4) belongs to chiral phosphine ligands. Generally, the efficiency of nucleophilic phosphine catalysis often depends on the nature of the tertiary phosphine. Most of these phosphines are acyclic, usually possess low nucleophilic activity, and generally display poor enantioselectivities for phosphine organocatalysis. Computed Properties of C52H44N2O2P2

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis

Dynamic kinetic asymmetric allylation of hydrazines and hydroxylamines was written by Mangion, Ian;Strotman, Neil;Drahl, Michael;Imbriglio, Jason;Guidry, Erin. And the article was included in Organic Letters in 2009.SDS of cas: 174810-09-4 This article mentions the following:

Hydrazines and hydroxylamines have been found to be excellent nucleophiles for the palladium-catalyzed dynamic asym. allylic amination of vinyl epoxide, with good yields and enantioselectivities of up to 97% ee. This method is applicable to acyclic and heterocyclic amines and was applied toward a five-step synthesis of (R)-piperazic acid. In the experiment, the researchers used many compounds, for example, N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4SDS of cas: 174810-09-4).

N,N’-((1R,2R)-Cyclohexane-1,2-diyl)bis(2-(diphenylphosphino)-1-naphthamide) (cas: 174810-09-4) belongs to chiral phosphine ligands. Phosphine-catalyzed asymmetric reactions are now powerful and versatile tools for the construction of C–C, C–N, C–O, and C–S bonds and for the syntheses of functionalized carbocycles and heterocycles. Chiral phosphine catalysts: Nucleophilic phosphine catalysis often involves the formation of Lewis adducts, namely phosphonium (di)enolate zwitterions, as reaction intermediates.SDS of cas: 174810-09-4

Referemce:
Phosphine ligand,
Chiral phosphines in nucleophilic organocatalysis