Addition Of Phosphite Research Articles

Asymmetric organocatalytic conjugate addition of dialkyl phosphites to N-unprotected isatylidene malononitriles: access to 3-phospho-2-oxindoles with chiral quaternary stereocenters

The enantioselective Michael addition of dialkyl phosphites to N-unprotected isatylidene malononitriles has been established for the first time by using a simple bifunctional tertiary amine–thiourea catalyst. The corresponding adducts, 3-phospho-2-oxindoles, containing a chiral quaternary carbon center at the 3-position of the oxindole, were obtained in good to excellent yields (up to 98%) with moderate to excellent enantioselectivities (up to 95% ee). In addition, optically active 3,3′-disubstituted oxindoles bearing carboxylate and phosphonate groups were facilely obtained by the oxidative degradation of the Michael adducts.

ChemInform Abstract: Lanthanide‐Catalyzed Selective Addition of Diethyl Phosphite to Chalcones.

AbstractLanthanide complexes efficiently catalyze the phospha‐Michael addition of diethyl phosphite to chalcones yielding phosphonates of type (III) or (V) depending on the ratio of the reactants.

Stereoselective addition of dialkyl phosphites to di-salicylaldimines bearing the (R,R)-1,2-diaminocyclohexane moiety

The addition of dialkyl phosphites to the azomethine bond of N,N′-disalicylidene-1,2-diaminocyclohexane imines, catalyzed by sodium hydride led to bis-aminophosphonates in a high diastereoselectivity. One of the bis-aminophosphonates was analyzed by X-ray diffraction. Another bis-aminophosphonate was converted to a bis-aminophosphonic acid and the structure was studied by X-ray diffraction. Addition of phosphites to a diimine resulted in an aminophosphonate, which was also studied by X-ray diffraction. An explanation of the diastereoselectivity is suggested.

First example of quinine-squaramide catalyzed enantioselective addition of diphenyl phosphite to ketimines derived from isatins

A highly enantioselective addition of diphenyl phosphite to ketimines derived from isatins has been achieved using a bifunctional organocatalyst, quinine-derived squaramide catalyst. This method works efficiently with several ketimines to produce the corresponding 3-amino-2-oxoindolin-3-yl-phosphonates in excellent yields with high enantioselectivity (up to 98% ee).

Asymmetric Synthesis of α-Aminophosphonate Esters by the Addition of Dialkyl Phosphites to tert-Butanesulfinyl Imines

The KHMDS-mediated addition of dialkyl phosphites to N - tert -butanesulfinyl aldimines and ketimines proceeds in uniformly high yields and diastereoselectivities and thereby enables the rapid and general asymmetric synthesis of α-aminophosphonate esters.

Stereochemistry of Phosphite Addition to Azomethine Bond of Achiral 2,6-Pyridinedicarbaldimines and Isophthalaldimines—A Comparative Study

The addition of dialkyl H-phosphonates to isophthalaldimines 1a–d and pyridine-2,6-dicarboxaldimines 2a–d was investigated and led to the corresponding aminophosphonates. Diastereoselectivity of the addition to pyridine-2,6-dicarboxaldimines was lower than to isophthalaldimines. In contrast, addition of bis(trimethylsilyl) H-phosphonate to both groups of aldimines demonstrated that the diastereoselectivity in case of pyridine-2,6-dicarboxaldimines is comparable or even better than that for the isophthalic derivatives.

Novel Lanthanide Amides Incorporating Neutral Pyrrole Ligand in a Constrained Geometry Architecture: Synthesis, Characterization, Reaction, and Catalytic Activity

The first series of lanthanide amido complexes incorporating a neutral pyrrole ligand in a constrained geometry architecture were synthesized, and their bonding, reactions, and catalytic activities were studied. Treatment of [(Me3Si)2N]3Ln(μ-Cl)Li(THF)3 with 1 equiv of (N-C6H5NHCH2CH2)(2,5-Me2C4H2N) (1) afforded the first example of bisamido lanthanide complexes having the neutral pyrrole η5-bonded to the metal formulated as [η5:η1-(N-C6H5NCH2CH2)(2,5-Me2C4H2N)]Ln[N(SiMe3)2]2 (Ln = La (2) and Nd (3)). Reaction of [(Me3Si)2N]3Sm(μ-Cl)Li(THF)3 with 2 equiv of 1 produced the complex [η5:η1-(N-C6H5NCH2CH2)(2,5-Me2C4H2N)][η1-(N-C6H5NCH2CH2)(2,5-Me2C4H2N)]]SmN(SiMe3)2 (4). Treatment of 3 with 2 equiv of 1 gave the sandwich neodymium complex [η5:η1-(N-C6H5NCH2CH2)(2,5-Me2C4H2N)]2Nd[η1-(N-C6H5NCH2CH2)(2,5-Me2C4H2N)] (5), in which two neutral pyrroles bonded with metal in an η5 mode. Complex 5 could also be prepared by reaction of [(Me3Si)2N]3Nd(μ-Cl)Li(THF)3 with 3 equiv of 1. Reactivities of the lanthanide bisamido complexes were further investigated. Reaction of complex 2 with pyrrolyl-functionalized imine [2-(2,6-iPr2C6H3N═CH)C4H3NH] afforded a mixed η5-bonded neutral pyrrole and η1-bonded anionic pyrrolyl lanthanum complex [η5:η1-(N-C6H5NCH2CH2)(2,5-Me2C4H2N)]{η1-2-[(2,6-iPr2C6H3)NCH]C4H3N}La[N(SiMe3)2] (6). Reactions of complexes 2 and 3 with pyrrolyl-functionalized secondary amine afforded the mixed η5-bonded neutral pyrrole and the η1-bonded anionic pyrrolyl lanthanide complexes [η5:η1-(N-C6H5NCH2CH2)(2,5-Me2C4H2N)][(η1-2-tBuNCH)C4H3N]2Ln (Ln = La (7), Nd (8)) with dehydrogenation of the secondary amine. Investigation of the catalytic properties of complexes 2–8 indicated that all complexes exhibited a high activity with a high chemo- and regioselectivity on the addition of dialkyl phosphite to α,β-unsaturated carbonyl derivatives. An interesting result was found that 1,2-hydrophosphonylation substrates could be catalytically converted to 1,4-hydrophosphinylation products when the substrates are the substituted benzylideneacetones by controlling the reaction conditions.

Lanthanide‐Catalyzed Selective Addition of Diethyl Phosphite to Chalcones

ABSTRACTLanthanide‐catalyzed addition of diethyl phosphite with chalcones was achieved under mild conditions. The reaction exhibited good product selectivity using different catalysts. γ‐Oxophosphonates were obtained in high yields in the reactions catalyzed by Yb(OAr)3(THF)2, while those catalyzed by [(Me3Si)2N]3La(μ‐Cl)Li(THF)3 afforded 1,2‐oxaphospholane‐5‐phosphonates as the main products in moderate to good yields. This methodology provides facile and practical approaches to the corresponding organophosphorus compounds with biological interest.

An Efficient Conjugate Addition of Dialkyl Phosphite to Electron-Deficient Olefins: The Use of a Nucleophilic Organocatalyst to Form a Strong Base

School of Applied Chemical Engineering, Chonnam National University, Gwangju 500-757, KoreaReceived December 12, 2012, Accepted December 30, 2012Key Words : Conjugate addition, Dialkyl phosphite, Electron-deficient olefins, OrganocatalystThe formation of a zwitterionic species between electron-deficient olefins and tertiary amine or phosphine is a pivotaland the starting point for the Morita-Baylis-Hillman (MBH)reaction

Phospha-Michael addition of diethyl phosphite to α,β-unsaturated malonates catalyzed by nano γ-Fe2O3-pyridine based catalyst as a new magnetically recyclable heterogeneous organic base

Nano γ-Fe2O3-pyridine based catalyst as a new magnetically recyclable heterogeneous organic base was synthesized. The synthesized odorless pyridine based catalyst was used as a new catalyst for the efficient synthesis of β-phosphonomalonates by the reaction of diethyl phosphite with α,β-unsaturated malonates. The catalyst was easily isolated from the reaction mixture by a magnetic bar and reused at least 10 times without significant degradation in the activity.

Recent advances in the synthesis of fluorinated aminophosphonates and aminophosphonic acids

This review article surveys recent achievements in the preparation and biological properties evaluation of fluorinated aminophosphonates and aminophosphonic acids. Recently, in view of various important biological applications of the fluorinated aminophosphonic acid derivatives, the development of suitable synthetic methodologies for their preparation in racemic and in optically pure form has been a topic of great interest. Considerable progress has been made in asymmetric synthesis of fluorinated acyclic aminophosphonates and aminophosphonic acids using catalytic enantioselective reduction of fluorinated α-iminophosphonates, catalytic enantioselective addition of alkyl phosphites to fluorinated imines, and diastereoselective addition of alkyl phosphites to chiral fluorinated imines. A new efficient access to CF3-substituted cyclic α-aminophosphonates has been developed based on metal-catalyzed carbene transfer reactions with diethyl 1-diazo-2,2,2-trifluoroethylphosphonate. New processes, e.g. enantioselective alkynylation and nucleophilic aromatic substitution involving fluorinated substrates are also considered.

Environmentally Friendly Syntheses and Tools

Recent results obtained by our group on MW-assisted reactions, such as the alkylation of P˭O-functionalized CH-acidic compounds and the addition of dialkyl phosphites to α-ketophosphonates, are summarized together with the rational synthesis of hydroxy-methylene bis(phosphinic acids).

Trivalent organophosphorus reagent induced pinacol rearrangement of 4H-cyclopenta[2,1-b:3,4-b′]dithiophen-4-one

In this Letter we report on the reaction of 4H-cyclopenta[2,1-b:3,4-b′]dithiophen-4-one with various trivalent organophosphorus derivatives, with an emphasis on the final products depending on the applied reagents. No reaction occurred upon treatment with either triphenyl- or tricyclohexylphosphine, whereas addition of triethyl phosphite or tri(n-butyl)phosphine resulted in pinacol rearrangement. Structure elucidation of the isolated 5H-spiro(benzo[1,2-b:6,5-b′]dithiophene-4,4′-cyclopenta[2,1-b:3,4-b′]dithiophen)-5-one was achieved by combined NMR experiments, theoretical chemical shift and geometry calculations, and single crystal X-ray analysis.

ChemInform Abstract: An Efficient Synthesis of Enol Phosphates via Organic Base‐Promoted Addition of Phosphites to 4‐Oxo‐enoates.

AbstractA practical, mild, and convenient protocol for the synthesis of the title compounds is described by using a simple and cheap catalyst.

3‐P⩵O‐Functionalized Phospholane 1‐Oxides by the Michael Reaction of 1‐Phenyl‐2‐phospholene 1‐Oxide and Dialkyl Phosphites, H‐Phosphinates, or Diphenylphosphine Oxide

ABSTRACTThe addition of dialkyl phosphites, H‐phosphinates, and diphenylphosphine oxide on the β carbon atom of the not too reactive double bond of 1‐phenyl‐2‐phospholene 1‐oxide was carried out in two ways. According to the first approach (A), the P‐reagents were activated by trimethylaluminum prior to the Michael addition. The second method (B) involved the microwave(MW)‐assisted solventless reaction of the P‐species with the phospholene oxide. In general, method A was more efficient and more selective than route B. However, the addition of dialkyl phosphites and diphenylphosphine oxide could also be accomplished well under MW conditions. The disadvantage of the MW‐assisted approach is that the Michael adducts are formed as a mixture of isomers. The 3‐P⩵O‐phospholane oxides are novel products, and among these, the bis(phosphine oxide) is the precursor of the bidentate P‐ligand LuPhos.

ChemInform Abstract: Addition of Dimethyl Phosphite to Imines Bearing the L‐Methionine Moiety and Its Surprisingly Poor Chiral Assistance.

AbstractAddition of dimethyl phosphite to L‐methionine‐derived azomethines (I) does not show significant diastereoselectivity as known from other amino acids, e.g. L‐leucine.

ChemInform Abstract: Microwave‐Assisted Phospha‐Michael Addition of Dialkyl Phosphites, a Phenyl‐H‐phosphinate, and Diphenylphosphine Oxide to Maleic Derivatives.

AbstractA variety of new P‐substituted succinic acid derivatives is synthesized via microwave‐assisted phospha‐Michael addition of phosphites, phosphinates or phosphine oxides to maleimide or maleic acid derivatives.

ChemInform Abstract: The Asymmetric Synthesis of Chiral Cyclic α‐Hydroxy Phosphonates and Quaternary Cyclic α‐Hydroxy Phosphonates.

AbstractA dialuminum complex derived in situ from chiral tridentate Schiff Base TSB in combination with silver carbonate catalyzes the addition of cyclic phosphite (II) to aldehydes or ketones to give the title phosphonates with up to 99% enantioselectivity.

Synthesis of new N-arylamino(2-furyl)methylphosphonic acid diesters, and in vitro evaluation of their cytotoxicity against esophageal cancer cells

N-Furfurylideneanilines and N-arylamino(2-furyl)methylphosphonates with tolyl and anisyl moieties were synthesized by the addition of phosphites to azomethine bond of corresponding Schiff bases and their NMR spectroscopic properties were investigated. Then, they were analyzed in the point of view of their influence on KYSE 30, KYSE 150, and KYSE 270 esophageal cancer cell lines and on immortalized esophageal cell line HET 1 A as a control group. Toxicity was evaluated by MTT assay. Among 11 compounds, a few of them demonstrated influence on cancer cells being neutral toward the control, but only one aminophosphonate had IC50 lower than 100 μM and acted as a potential anticancer drug. Some approaches to structure–activity relation were performed.

An efficient synthesis of enol phosphates via organic base-promoted addition of phosphites to 4-oxo-enoates

A TMG catalyzed, practical and efficient hydrophosphorylation of 4-oxo-enoates by diethyl or diphenyl phosphite has been described. This protocol allows a convenient access to a variety of enol phosphates under mild conditions in good yield with excellent stereoselectivity.