873-63-2Relevant articles and documents
Combination of Asymmetric Organo- and Biocatalysis in Flow Processes and Comparison with their Analogous Batch Syntheses
Gr?ger, Harald,Hanefeld, Ulf,Schober, Lukas,Tonin, Fabio
supporting information, (2022/03/01)
A sequential-type as well as a tandem-type chemoenzymatic flow cascade combining an organocatalytic aldol reaction and a biocatalytic reduction to form stereoselectively a 1,3-diol with two stereogenic centers were developed. Initially, a comprehensive screening of 24 alcohol dehydrogenases was carried out and the identified candidates were applied in different multi-step flow cascades. All four stereoisomers of the desired 1,3-diol product are accessible via a sequential flow approach with product formation-related conversions of up to 76 % over two steps, isolated yields of up to 64 % and enantiomeric excess of >99 % in all cases. In addition, a tandem-type flow process, performing both reaction steps simultaneously, was established leading to 51 % conversion with >99 % ee and 8 : 1 d.r. and representing a combination of the fields of asymmetric chemocatalysis, biocatalysis and flow chemistry.
Homoleptic cobalt(II) phenoxyimine complexes for hydrosilylation of aldehydes and ketones without base activation of cobalt(II)
Hori, Momoko,Ishikawa, Ryuta,Koga, Yuji,Matsubara, Kouki,Mitsuyama, Tomoaki,Shin, Sayaka
, p. 1379 - 1387 (2021/05/29)
Air-stable, easy to prepare, homoleptic cobalt(II) complexes bearing pendant-modified phenoxyimine ligands were synthesized and determined. The complexes exhibited high catalytic performance for reducing aldehydes and ketones via catalytic hydrosilylation, where a hydrosilane and a catalytic amount of the cobalt(II) complex were added under base-free conditions. The reaction proceeded even in the presence of excess water, and excellent functional-group tolerance was observed. Subsequent hydrolysis gave the alcohol in high yields. Moreover, H2O had a critical role in activation of the Co(II) catalyst with hydrosilane. Several additional results also indicated that the cobalt(II) center acts as an active catalyst in the hydrosilylation of aldehydes and ketones.
Designing of Highly Active and Sustainable Encapsulated Stabilized Palladium Nanoclusters as well as Real Exploitation for Catalytic Hydrogenation in Water
Patel, Anish,Patel, Anjali
, p. 803 - 820 (2020/08/12)
Abstract: Encapsulated nanoclusters based on palladium, 12-tunstophosphoric acid and silica was designed by simple wet impregnation methodology. The catalyst was found to be very efficient towards cyclohexene hydrogenation up to five catalytic runs with substrate/catalyst ratio of 4377/1 at 50?°C as well as for alkene, aldehyde, nitro and halogen compounds. Graphic Abstract: Silica encapsulated Pd nanoclusters stabilized by 12-tungstophosphoric acid is proved to be sustainable and excellent for water mediated hydrogenation reaction with very high catalyst to substrate ratio as well as TON.[Figure not available: see fulltext.]
