Ring‐Opening Reactions of 3‐Aryl‐1‐benzylaziridine‐2‐carboxylates and Application to the Asymmetric Synthesis of an Amphetamine‐Type Compound

Nucleophilic ring‐opening reactions of 3‐aryl‐1‐benzylaziridine‐2‐carboxylates were examined by using O‐nucleophiles and aromatic C‐nucleophiles. The stereospecificity was found to depend on substrates and conditions used. Configuration inversion at C(3) was observed with O‐nucleophiles as a major reaction path in the ring‐opening reactions of aziridines carrying an electron‐poor aromatic moiety, whereas mixtures containing preferentially the syn‐diastereoisomer were generally obtained when electron‐rich aziridines were used (Tables 1–3). In the reactions of electron‐rich aziridines with C‐nucleophiles, S_N2 reactions yielding anti‐type products were observed (Table 4). Reductive ring‐opening reaction by catalytic hydrogenation of (+)‐trans‐(2S,3R)‐3‐(1,3‐benzodioxol‐5‐yl)aziridine‐2‐carboxylate (+)‐trans‐ 3c afforded the corresponding α‐amino acid derivative, which was smoothly transformed into (+)‐tert‐butyl [(1R)‐2‐(1,3‐benzodioxol‐5‐yl)‐1‐methylethyl]carbamate((+)‐ 14 ) with high retention of optical purity (Scheme 6).     

Far‐ and Deep‐Ultraviolet Surface Plasmon Resonance Sensor

Plasmonics in the UV region has been widely focused because of the higher energy and the abundant electronic resonances compared to the conventional visible plasmonics. Recently, we have investigated the surface plasmon resonance (SPR) properties of the Al film, aiming for the application as refractive index sensors. Utilizing the UV lights, we expect three advantages: high sensitivity, material selectivity, and surface selectivity. By using an original attenuated total reflectance spectroscopic instrument, Al‐SPR angle and wavelength were investigated with changing environments on the Al film. Al film thickness and materials of prisms on which Al was evaporated were also important factors for the SPR properties. By optimizing the conditions, the Al film worked as a sensor both in air and in liquids. In addition, our established system expands the plasmonics into an even higher energy region than 200 nm, while the UV‐plasmonics have been studied in the wavelength region longer than 200 nm.     

A novel hydrazide type organocatalyst for enantioselective Diels-Alder reactions

The development of a new class of hydrazide type organocatalyst, (4R,5R)-1,3-bis(isopropylamino)-4,5-dihenylimidazolidin-2-one 2a, for enantioselective Diels-Alder reactions between cyclopentadiene and α,β-unsaturated aldehydes are presented. The new organocatalyst 2a promoted the reaction, affording Diels-Alder adducts in good yields with good levels of enantioselectivity.     

Synthesis of glutamate by reductive amination of 2-oxoglutarate with the combination of hydrogenase and glutamate dehydrogenase

Glutamate synthesis by reductive amination of 2-oxoglutarate was performed by the combination of NADH regeneration system and glutamate dehydrogenase (GluDH). The conversion of 2-oxoglutamate to glutamate was 98% after 3 h, and the turnover number of NAD⁺was 17.