21307-96-0

Upstream product

• 498-21-5 2-methylbutanedioic acid 
• 67-56-1 methanol 
• 73964-90-6 5-methyl-(3H,5H)-tetrahydrothiophene-2,4-dione 
• 616-02-4 citraconic acid anhydride 
• 617-52-7 Dimethyl itakonate 
• 4100-80-5 2-methylsuccinic anhydride 
• 186581-53-3 diazomethane 
• 7214-52-0 3,5-dimethyl-cyclohexanone 
• 617-86-7 triethylsilane 
• 75-36-5 acetyl chloride 
• 513-42-8 3-hydroxy-2-methyl-1-propene 
• 201230-82-2 carbon monoxide 
• 80-62-6 methacrylic acid methyl ester 
• 3674-77-9 2-methyl-2-phenyl-1,3-dioxolane 

Downstream Products

• 1467-37-4 (+/-)-2-((E)-benzylidene)-3-methyl-succinic acid 
• 83509-04-0 (R)-2-methylsuccinate-1-monomethyl ester 
• 111266-16-1 L-malic acid methyl ester 
• 23268-03-3 3-methoxycarbonyl-2-R-methylpropionic acid 
• 56108-32-8 methyl-succinic acid dipropyl ester 
• 111195-88-1 (R)-2-Methyl-succinic acid 4-methyl ester 1-propyl ester 
• 111195-87-0 (R)-2-Methyl-succinic acid 1-methyl ester 4-propyl ester 
• 111195-87-0 (S)-2-Methyl-succinic acid 1-methyl ester 4-propyl ester 
• 111195-87-0 2-Methyl-succinic acid 1-methyl ester 4-propyl ester 
• 22644-27-5 (R)-methylsuccinic acid dimethyl ester 
• 412012-73-8 2-Methyl-4-(3-methoxy-2-benzyloxy-phenyl)-3-methoxycarbonyl-buten-⁽³⁾-saeure-⁽¹⁾ 
• 23268-03-3 (R)-2-methyl-succinic acid 4-methyl ester 
• 1604-11-1 (S)-dimethyl 2-methylsuccinate 
• 957209-44-8 2,2,3-trifluoro-3-trifluoromethyl-butanedioyl difluoride 

Relevant academic research and scientific papers

Using Data Science To Guide Aryl Bromide Substrate Scope Analysis in a Ni/Photoredox-Catalyzed Cross-Coupling with Acetals as Alcohol-Derived Radical Sources

Ni/photoredox catalysis has emerged as a powerful platform for C(sp2)–C(sp3) bond formation. While many of these methods typically employ aryl bromides as the C(sp2) coupling partner, a variety of aliphatic radical sources have been investigated. In principle, these reactions enable access to the same product scaffolds, but it can be hard to discern which method to employ because nonstandardized sets of aryl bromides are used in scope evaluation. Herein, we report a Ni/photoredox-catalyzed (deutero)methylation and alkylation of aryl halides where benzaldehyde di(alkyl) acetals serve as alcohol-derived radical sources. Reaction development, mechanistic studies, and late-stage derivatization of a biologically relevant aryl chloride, fenofibrate, are presented. Then, we describe the integration of data science techniques, including DFT featurization, dimensionality reduction, and hierarchical clustering, to delineate a diverse and succinct collection of aryl bromides that is representative of the chemical space of the substrate class. By superimposing scope examples from published Ni/photoredox methods on this same chemical space, we identify areas of sparse coverage and high versus low average yields, enabling comparisons between prior art and this new method. Additionally, we demonstrate that the systematically selected scope of aryl bromides can be used to quantify population-wide reactivity trends and reveal sources of possible functional group incompatibility with supervised machine learning.

Mechanistically Guided One Pot Synthesis of Phosphine-Phosphite and Its Implication in Asymmetric Hydrogenation

Although hybrid bidentate ligands are known to yield highly enantioselective products in asymmetric hydrogenation (AH), synthesis of these ligands is an arduous process. Herein, a one pot, atom-economic synthesis of a hybrid phosphine-phosphite (L1) is reported. After understanding the reactivity difference between an O-nucleophile versus C-nucleophile, one pot synthesis of Senphos (L1) was achieved (72 %). When L1 was treated with [Rh], 31P NMR revealed bidentate coordination to Rh. Senphos, in the presence of rhodium, catalyzes the AH of Methyl-2-acetamido-3-phenylacrylate and discloses an unprecedented turn over frequency of 2289, along with excellent enantio-selectivity (92 %). The generality is demonstrated by hydrogenating an array of alkenes. The AH operates under mild conditions of 1–2 bar H2 pressure, at room temperature. The practical relevance of L1 is demonstrated by scaling-up the reaction to 1 g and by synthesizing DOPA, a drug widely employed for the treatment of Parkinson's disease. Computational insights indicate that the R isomer is preferred by 3.8 kcal/mol over the S isomer.

Chiral phosphine-phosphoramidite ester ligand as well as preparation method and application thereof

The invention provides a method for preparing a phosphine-phosphoramidite ester ligand from a chiral beta-aminophosphine intermediate and an application of the phosphine-phosphoramidite ester ligand in an asymmetric reaction. Chiral N-(2-(phosphoryl)-1-phenethyl) amide is prepared from the chiral beta-aminophosphine intermediate through an asymmetric hydrogenation reaction of (Z)-(alpha-aryl-beta-phosphoryl) alkenyl amide, and then hydrolysis reduction. The preparation method comprises the following steps: dissolving newly-prepared chlorinated phosphite in toluene, adding a solution formed by dissolving the chiral phosphine-amine compound and triethylamine in toluene into an ice-water bath according to a molar ratio of the chiral phosphine-amine compound to the chlorinated phosphite to the triethylamine of 1: (1-2): (3-5), heating the reaction solution to 18-25 DEG C, stirring and reacting for 10-30 hours, filtering, and carrying out column chromatography to remove the solvent, and recrystallizing to obtain the required phosphine-phosphoramidite ligand. According to the present invention, the asymmetric hydrogenation reaction of the catalyst formed by the ligand and the metal precursor on the double bonds such as C = C, C = N, C = O and the like can achieve the enantioselectivity of 99%; the catalyst is high in activity, and TON reaches up to 10000.

PHANE-TetraPHOS, the First D2 Symmetric Chiral Tetraphosphane. Synthesis, Metal Complexation, and Application in Homogeneous Stereoselective Hydrogenation

PHANE-TetraPHOS, a new D2 symmetric tetraphosphane based on the [2.2]paracyclophane scaffold, has been synthesized and characterized. The peculiarity of this system is the presence of four homotopic diphenylphosphane groups, exchangeable through C2 symmetry operations and consequently indistinguishable. Their spatial arrangement allows the simultaneous complexation of two metal atoms. Enantiomeric purity was attained at tetra-phosphane oxide level by fractional crystallization of the diastereomeric adducts obtained from the racemate with enantiopure dibenzoyltartaric acids. Alkaline treatment of diastereomerically pure adducts followed by exhaustive P?O groups reduction with HSiCl3 gave both PHANE-TetraPHOS antipodes in an enantiopure state. They were tested as rhodium ligands in the homogeneous enantioselective hydrogenation of some benchmark unsaturated compounds. Catalytic activity and enantiodiscrimination ability were found comparable to those exhibited by the complexes of the parent bidentate ligand PHANEPHOS, but only half a mole of precious chiral ligand was employed.

A robust and stereocomplementary panel of ene-reductase variants for gram-scale asymmetric hydrogenation

We report an engineered panel of ene-reductases (ERs) from Thermus scotoductus SA-01 (TsER) that combines control over facial selectivity in the reduction of electron deficient C[dbnd]C double bonds with thermostability (up to 70 °C), organic solvent tolerance (up to 40 % v/v) and a broad substrate scope (23 compounds, three new to literature). Substrate acceptance and facial selectivity of 3-methylcyclohexenone was rationalized by crystallisation of TsER C25D/I67T and in silico docking. The TsER variant panel shows excellent enantiomeric excess (ee) and yields during bi-phasic preparative scale synthesis, with isolated yield of up to 93 % for 2R,5S-dihydrocarvone (3.6 g). Turnover frequencies (TOF) of approximately 40 000 h?1 were achieved, which are comparable to rates in hetero- and homogeneous metal catalysed hydrogenations. Preliminary batch reactions also demonstrated the reusability of the reaction system by consecutively removing the organic phase (n-pentane) for product removal and replacing with fresh substrate. Four consecutive batches yielded ca. 27 g L?1 R-levodione from a 45 mL aqueous reaction, containing less than 17 mg (10 μM) enzyme and the reaction only stopping because of acidification. The TsER variant panel provides a robust, highly active and stereocomplementary base for further exploitation as a tool in preparative organic synthesis.

Generation of Functionalized Alkyl Radicals via the Direct Photoexcitation of 2,2′-(Pyridine-2,6-diyl)diphenol-Based Borates

A new type of alkylborate was developed for the purpose of generating radicals via direct photoexcitation. These borates were prepared using 2,2′-(pyridine-2,6-diyl)diphenol as a tridentate ligand together with organoboronic acids or potassium trifluoroborates. The ready availability of organoboron compounds is a significant advantage of this direct photoexcitation protocol. The excited states of these borates can also serve as strong reductants, enabling various transformations.

P-chirogenic diphosphazanes with axially chiral substituents and their use in rh-catalyzed asymmetric hydrogenation

A convenient synthesis of enantiopure P-chirogenic diphosphazanes incorporating bulky bisphenol and 1,1′-bi-2-naphtholderived substituents via the functionalization of a readily accessible enantiopure lithium phosphinoamide with chlorophosphoridites was developed. Since the product requires no subsequent deprotection, the protocol provides an easy, convenient synthesis of P-chirogenic ligands on the gram scale. The ligands were applied in the Rh-catalyzed asymmetric hydrogenation of benchmark substrates furnishing enantiomeric excess values up to 96%.

Photocatalytic Hydromethylation and Hydroalkylation of Olefins Enabled by Titanium Dioxide Mediated Decarboxylation

A versatile method for the hydromethylation and hydroalkylation of alkenes at room temperature is achieved by using the photooxidative redox capacity of the valence band of anatase titanium dioxide (TiO2). Mechanistic studies support a radical-based mechanism involving the photoexcitation of TiO2 with 390 nm light in the presence of acetic acid and other carboxylic acids to generate methyl and alkyl radicals, respectively, without the need for stoichiometric base. This protocol is accepting of a broad scope of alkene and carboxylic acids, including challenging ones that produce highly reactive primary alkyl radicals and those containing functional groups that are susceptible to nucleophilic substitution such as alkyl halides. This methodology highlights the utility of using heterogeneous semiconductor photocatalysts such as TiO2 for promoting challenging organic syntheses that rely on highly reactive intermediates.

Inexpensive and rapid hydrogenation catalyst from CuSO4/CoCl2 — Chemoselective reduction of alkenes and alkynes in the presence of benzyl protecting groups

The simple reduction of a number of alkenes and alkynes was performed with a typical reaction time of 20 min using a copper-cobalt catalytic system. The reduction did not cleave benzyl protecting groups which are usually vulnerable to catalytic hydrogenation reactions. The catalyst can be prepared in situ by reduction of the inexpensive precursor salts CuSO4 and CoCl2 with NaBH4. Sodium borohydride was also used as an easily handled hydrogen source for the catalytic reductions. No pressure, heating or inert atmosphere is required and purification/catalyst removal is achieved using extraction procedures, making this approach simple and efficient.

Modular 1,1′-Ferrocenediyl-cored P-Stereogenic Diphosphines: ′′JDayPhos′′ Series and its Use in Rhodium(I)-Catalyzed Hydrogenation

A novel ferrocene-based P-stereogenic diphospine ligand series dubbed JDayPhos was developed, which rhodium(I) complexes of some of its members exhibited excellent enantioselectivity (up to >99% ee) and high activity in asymmetric hydrogenation of β-unsubstituted or -substituted itaconates and α-methylene-γ-oxo-carboxylates. (Figure presented.).