22148-79-4

Upstream product

• 22374-89-6 (RS)-1-methyl-3-phenylpropylamine 
• 141-78-6 ethyl acetate 
• 2550-26-7 4-Phenyl-2-butanone 
• 140-88-5 ethyl acrylate 
• 108-24-7 acetic anhydride 
• 2344-70-9 (+)-(S)-4-phenylbutan-2-ol 
• 4187-57-9 (S)-1-methyl-3-phenylpropylamine 
• 16520-62-0 4-Phenyl-1-butyne 
• 536-74-3 phenylacetylene 
• 1817-57-8 4-phenyl-3-butyne-2-one 
• 28164-29-6 4-phenylbut-3-yn-2-one oxime 
• 1373120-09-2 N-(4-phenylbut-1-en-2-yl)acetamide 
• 116199-45-2 (S)-1-methyl-3-phenylpropyl azide 
• 108-21-4 Isopropyl acetate 

Relevant academic research and scientific papers

Direct Catalytic Asymmetric Reductive Amination of Aliphatic Ketones Utilizing Diphenylmethanamine as Coupling Partner

The highly efficient direct catalytic reductive amination of ketones with diphenylmethanamine catalyzed by iridium-phosphoramidite complexes is described. As an effective coupling partner, diphenylmethanamine is suitable for a wide range of ketones to pro

Cobalt-Catalyzed Chemo- and Enantioselective Hydrogenation of Conjugated Enynes

Asymmetric hydrogenation is one of the most powerful methods for the preparation of single enantiomer compounds. However, the chemo- and enantioselective hydrogenation of the relatively inert unsaturated group in substrates possessing multiple unsaturated bonds remains a challenge. We herein report a protocol for the highly chemo- and enantioselective hydrogenation of conjugated enynes while keeping the alkynyl bond intact. Mechanism studies indicate that the accompanying Zn2+ generated from zinc reduction of the CoII complex plays a critical role to initiate a plausible CoI/CoIII catalytic cycle. This approach allows for the highly efficient generation of chiral propargylamines (up to 99.9 % ee and 2000 S/C) and further useful chemical transformations.

Merging NiH Catalysis and Inner-Sphere Metal-Nitrenoid Transfer for Hydroamidation of Alkynes

The formal hydroamination/hydroamidation utilizing metal hydride is an appealing synthetic tool for the construction of valuable nitrogen-containing compounds from unsaturated hydrocarbons. While significant advances have been made for the functionalizations of alkenes in this realm, the direct hydroamidation of alkynes remains rather limited due to the high feasibility of the key metal-alkenyl intermediate to choose other reaction pathways. Herein, we report a NiH-catalyzed strategy for the hydroamidation of alkynes with dioxazolones, which allows convenient access to synthetically useful secondary enamides in (E)-anti-Markovnikov or Markovnikov selectivity. The reaction is viable for both terminal and internal alkynes and is also tolerant with a range of subtle functional groups. With H2O found as an essential component for high catalyst turnovers, the involvement of inner-sphere nitrenoid transfer is proposed that outcompetes an undesired semireduction process, thus representing the first example to show the competence of Ni catalysis for metal-nitrenoid formation from dioxazolones.

Two-Step Protocol for Iodotrimethylsilane-Mediated Deoxy-Functionalization of Alcohols

We have developed a two-step protocol for iodotrimethylsilane-mediated deoxy-functionalization of primary and secondary alcohols to afford products containing a C?N, C?S, or C?O bond. In the first step the alcohol undergoes iodination with iodotrimethylsilane, and in the second, the iodine atom is replaced by a N, S, or O nucleophile. Compared with traditional Mitsunobu reaction, non-acidic pre-nucleophiles can be used, and the reaction proceeds with retention of configuration. This operationally simple, highly efficient protocol can be used for some natural products and small-molecule drugs containing hydroxy-group.

Amine dehydrogenases: Efficient biocatalysts for the reductive amination of carbonyl compounds

Amines constitute the major targets for the production of a plethora of chemical compounds that have applications in the pharmaceutical, agrochemical and bulk chemical industries. However, the asymmetric synthesis of α-chiral amines with elevated catalytic efficiency and atom economy is still a very challenging synthetic problem. Here, we investigated the biocatalytic reductive amination of carbonyl compounds employing a rising class of enzymes for amine synthesis: amine dehydrogenases (AmDHs). The three AmDHs from this study-operating in tandem with a formate dehydrogenase from Candida boidinii (Cb-FDH) for the recycling of the nicotinamide coenzyme-performed the efficient amination of a range of diverse aromatic and aliphatic ketones and aldehydes with up to quantitative conversion and elevated turnover numbers (TONs). Moreover, the reductive amination of prochiral ketones proceeded with perfect stereoselectivity, always affording the (R)-configured amines with more than 99% enantiomeric excess. The most suitable amine dehydrogenase, the optimised catalyst loading and the required reaction time were determined for each substrate. The biocatalytic reductive amination with this dual-enzyme system (AmDH-Cb-FDH) possesses elevated atom efficiency as it utilizes the ammonium formate buffer as the source of both nitrogen and reducing equivalents. Inorganic carbonate is the sole by-product.

A Single Lipase-Catalysed One-Pot Protocol Combining Aminolysis Resolution and Aza-Michael Addition: An Easy and Efficient Way to Synthesise β-Amino Acid Esters

A novel one-pot protocol combining aza-Michael addition and aminolysis resolution was developed to obtain chiral β-amino acid esters with lipase B from Candida antarctica (CAL-B) as the only catalyst. This method is conducted under mild reaction conditions and is very easy to handle. After a series of detailed optimization studies, ten racemic aromatic or aliphatic amines were subjected to this one-pot procedure, and twelve chiral β-amino acid esters and ten chiral amides were successfully synthesised with excellent ee values in theoretical yields. Scaled-up procedures also worked without apparent reduction in reaction rate or enantioselectivity, which makes this method suitable for large-scale production of chiral β-amino acid esters. A one-pot protocol for simultaneous synthesis of chiral β-amino acid esters and amides was developed by combining single lipase B from Candida antarctica (CAL-B) catalysed aza-Michael addition and aminolysis resolution. This method requires mild reaction conditions and is very easy to handle. Chiral β-amino acid esters and chiral amides were obtained with excellent ee values and in theoretical yields.

Asymmetric Biocatalytic Amination of Ketones at the Expense of NH3 and Molecular Hydrogen

A biocatalytic system is presented for the stereoselective amination of ketones at the expense of NH3 and molecular hydrogen. By using a NAD+-reducing hydrogenase, an alanine dehydrogenase, and a suitable ω-transaminase, the R- as well as the S-enantiomer of various amines could be prepared with up to >99% ee and 98% conversion. (Chemical Equation Presented).

How the mode of Candida antarctica lipase B immobilization affects the continuous-flow kinetic resolution of racemic amines at various temperatures

The effect of temperature on enantiomeric ratio (E) and specific reaction rate (rflow) in the continuous-flow mode acetylation of (±)-1-phenylethanamine (rac-1a), (±)-4-phenylbutan-2-amine (rac-1b) and (±)-1,2,3,4-tetrahydro-1-naphthalenamine (rac-1c) by variously immobilized Candida antarctica lipase B biocatalysts was studied in the 0-70 °C range. In the continuous-flow kinetic resolutions with differently immobilized CaLB biocatalysts, the character of temperature effect depended significantly both on the substrate and on the mode of immobilization. Alteration of E in the kinetic resolutions of three differently flexible amines rac-1a-c as a function of temperature was rationalized by the various flexibility of the lipase in its different forms. Our results indicated that the optimal method of immobilization depended both on the nature of the substrate and the reaction conditions.

Amination of ketones by employing two new (S)-selective ω-transaminases and the his-tagged ω-TA from Vibrio fluvialis

Two recently identified (S)-selective ω-transaminases (ω-TAs) that originate from Paracoccus denitrificans (Strep-PD-ωTA, cloned with an N-terminal Strep-tag II) and Pseudomonas fluorescens (PF-ωTA) were employed for the asymmetric amination of selected prochiral ketones. The substrates tested were transformed into optically pure amines (>99 % ee) with high conversion (up to >99 %). The ω-TAs led to higher conversion in the absence of dimethyl sulfoxide as a cosolvent than in its presence (15 %, v/v). Additionally, it was shown that a His-tagged recombinant transaminase from Vibrio fluvialis (His-VF-ωTA, cloned with an N-terminal His 6-tag) showed for a single substrate, ethyl acetoacetate, significantly higher stereoselectivity for the amination compared to the corresponding commercial enzyme preparation (>99 vs. 50 %). The (S)-selective ω-transaminases (ω-TAs) from Paracoccus denitrificans and Pseudomonas fluorescens transformed various ketones into optically pure amines (>99 % ee). These enzymes extend the substrate spectrum of highly (S)-stereoselective ω-TAs. Copyright

Stereoselectivity of four (R)-selective transaminases for the asymmetric amination of ketones

Four (R)-ω-transaminases originating from Hyphomonas neptunium (HN-ωTA), Aspergillus terreus (AT-ωTA) and Arthrobacter sp. (ArR-ωTA), as well as an evolved transaminase (ArRmut11-ωTA) were successfully employed for the amination of prochiral ketones leading to optically pure (R)-amines. The first three transaminases displayed perfect stereoselectivity for the amination of all substrates tested (ee >99%). Furthermore, the transaminase AT-ωTA led in most cases to better conversion than ArR-ωTA and HN-ωTA using D-alanine as amine donor. α-Tetralone, which was the only substrate not accepted by HN-ωTA, ArR-ωTA, and AT-ωTA, was successfully transformed with perfect enantioselectivity (ee >99%) into the corresponding optically pure amine employing the variant ArRmut11-ωTA. Copyright