217446-14-5

Upstream product

• 108462-96-0 DL-N-(4-methoxybenzoyl)alanine 
• 501-53-1 benzyl chloroformate 
• 99553-79-4 2-(4-methoxyphenyl)-4-methyl-5-oxo-4,5-dihydrooxazole 
• 217446-08-7 5-benzyloxycarbonyloxy-4-methyl-2-(4-methoxyphenyl)-oxazole 

Relevant academic research and scientific papers

A step-economic and one-pot access to chiral Cα-tetrasubstituted α-amino acid derivatives: Via a bicyclic imidazole-catalyzed direct enantioselective C -acylation

Cα-Tetrasubstituted α-amino acids are ubiquitous and unique structural units in bioactive natural products and pharmaceutical compounds. The asymmetric synthesis of these molecules has attracted a lot of attention, but a more efficient method is still greatly desired. Here we describe the first sequential four-step acylation reaction for the efficient synthesis of chiral Cα-tetrasubstituted α-amino acid derivatives from simple N-acylated amino acids via an auto-tandem catalysis using a single nucleophilic catalyst. The synthetic efficiency is improved via a direct enantioselective C-acylation; the methodology affords the corresponding Cα-tetrasubstituted α-amino acid derivatives with excellent enantioselectivities (up to 99% ee). This step-economic, one-pot, and auto-tandem strategy provides facile access to important chiral building blocks, such as peptides, serines, and oxazolines, which are often used in medicinal and synthetic chemistry.

Single-Handed Helical Poly(quinoxaline-2,3-diyl)s Bearing Achiral 4-Aminopyrid-3-yl Pendants as Highly Enantioselective, Reusable Chiral Nucleophilic Organocatalysts in the Steglich Reaction

Helically chiral poly(quinoxaline-2,3-diyl)s bearing 4-aminopyrid-3-yl pendants were synthesized as new helical-polymer-based chiral nucleophilic organocatalysts. The obtained chiral nucleophilic polymer catalysts exhibited high catalytic activity, enantioselectivity, and reusability in asymmetric Steglich rearrangement of oxazolyl carbonate to C-carboxyazlactone. The polyquinoxaline-based, helically chiral DMAP catalyst mediated intramolecular acyl transfer selectively, by contrast with known small-molecule-based chiral organocatalysts, which also mediate intermolecular acyl transfers.

Asymmetric Nucleophilic Catalysis with an Octahedral Chiral-at-Metal Iridium(III) Complex

Herein, we report about the design, synthesis, and application of a nucleophilic octahedral chiral-only-at-metal iridium(III) complex. We demonstrate that the enantiopure form of this complex serves as an efficient catalyst for the asymmetric Steglich rearrangement of O-acylated azlactones (up to 96% ee and 99% yield) and the related asymmetric Black rearrangement of O-acylated benzofuranones (up to 94% ee and 99% yield). We provide insight into the mechanisms of these two acyl migration reactions and the catalyst's manner of chiral recognition with crystal structures of the active catalyst and a catalysis intermediate analog, as well as with quantum chemical calculations based on them. Furthermore, we demonstrate that the presented catalyst also efficiently catalyzes the asymmetric reaction between aryl alkyl ketenes and 2-cyanopyrrole to give the corresponding α-chiral N-acyl pyrroles (up to 95% ee and 99% yield).

Enantiodivergent Steglich rearrangement of O-carboxylazlactones catalyzed by a chirality switchable helicene containing a 4-aminopyridine unit

A pseudo-enantiomeric pair of optically switchable helicenes containing a catalytic 4-N-methylaminopyridine (MAP) bottom unit and a C2-symmetric, (10R,11R)-dimethoxymethyl-dibenzosuberane top template was synthesized. They underwent complementa

Efficient C-3 functionalization of 4-dimethylaminopyridine (DMAP). A straightforward access to new chiral nucleophilic catalysts

Herein, the straightforward C-3 functionalization of 4- dimethylaminopyridine (DMAP) backbone is disclosed. An efficient halogen-metal exchange procedure from 3-bromo DMAP 1 is reported providing a large panel of C-3 functionalized DMAPs. In addition, a Pd-catalysed C-N cross-coupling reaction is also described furnishing new 3-amino DMAPs. These new functionalization pathways led to the resolution-free synthesis of three new chiral DMAP catalysts in few steps and a good overall yield. These new catalysts were evaluated into the Steglich rearrangement giving modest enantioselectivities (up to 20% ee).

A dual-catalysis approach to the asymmetric steglich rearrangement and catalytic enantioselective addition of O-acylated azlactones to isoquinolines

A dual-catalysis approach, namely the combination of an achiral nucleophilic catalyst and a chiral anion-binding catalyst, was applied to the Steglich rearrangement to provide α,α-disubstituted amino acid derivatives in a highly enantioselective fashion. Replacement of the nucleophilic co-catalyst for isoquinoline resulted in a divergent reaction pathway and an unprecedented transformation of O-acylated azlactones. This strategy provided highly substituted α,β-diamino acid derivatives with excellent levels of stereocontrol.

Chiral bicycle imidazole nucleophilic catalysts: Rational design, facile synthesis, and successful application in asymmetric Steglich rearrangement

A new type of chiral bicycle imidazole nucleophilic catalyst was rationally designed, facilely synthesized, and successfully applied in an asymmetric Steglich rearrangement with good to excellent yield and enantioselectivity at ambient temperature. Moreov

A metallocene-pyrrolidinopyridine nucleophilic catalyst for asymmetric synthesis

A highly active chiral 4-aminopyridine nucleophilic catalyst, available in three steps from (S,S)-hexane-2,5-diol, was applied to the asymmetric Steglich rearrangement of O-aceylated azlactones (1 mol % loading, up to 76% ee).

Enantioselective TADMAP-catalyzed carboxyl migration reactions for the synthesis of stereogenic quaternary carbon

The chiral, nucleophilic catalyst TADMAP [1, 3-(2,2,2-triphenyl-1- acetoxyethyl)-4-(dimethylamino)-pyridine] has been prepared from 3-lithio-4-(dimethylamino)pyridine (5) and triphenylacetaldehyde (3), followed by acylation and resolution. TADMAP catalyzes the carboxyl migration of oxazolyl, furanyl, and benzofuranyl enol carbonates with good to excellent levels of enantioselection. The oxazole reactions are especially efficient and are used to prepare chiral lactams (23) and lactones (30) containing a quaternary asymmetric carbon. TADMAP-catalyzed carboxyl migrations in the indole series are relatively slow and proceed with inconsistent enantioselectivity. Modeling studies (B3LYP/6-31G*) have been used in qualitative correlations of catalyst conformation, reactivity, and enantioselectivity.

Enantioselective synthesis of 4-(dimethylamino)pyridines through a chemical oxidation-enzymatic reduction sequence. Application in asymmetric catalysis

Enantiomerically pure 4-(dimethylamino)-3-(1-hydroxyalkyl)pyridines and 4-(dimethylamino)-3-[hydroxy(phenyl)methyl]pyridine have been prepared through efficient chemoenzymatic routes. For this purpose different lipases and oxidoreductases have been tested