Naslov
Efficient Chemoenzymatic Dynamic Kinetic Resolution of 1-Heteroaryl Ethanols

Autori
Vallin, Karl S. A. ; Wensbo Posaric, David ; Hameršak, Zdenko ; Svensson, Mats A. ; Minidis, Alexander B. E.

Izvornik
Journal of Organic Chemistry (0022-3263) 74 (2009), 24; 9328-9336

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
Chemoenzymatic Dynamic Kinetic Resolution ; 1-Heteroaryl Ethanols

Sažetak
The scope and limitation of the combined ruthenium-lipase induced dynamic kinetic resolution (DKR) through O-acetylation of racemic heteroaromatic secondary alcohols, i.e., 1- heteroaryl substituted ethanols, was investigated. After initial screening of reaction conditions, Candida antarctica lipase B (Novozyme 435, N435) together with 4-chloro-phenylacetate as acetyl-donor for kinetic resolution (KR), in conjunction with the ruthenium-based Shvo catalyst for substrate racemization in toluene at 80
C, enabled DKR with high yields and stereoselectivity of various 1-heteroaryl ethanols, such as°oxadiazoles, isoxazoles, 1H-pyrazole, or 1H-imidazole. In addition, DFT calculations based on a simplified catalyst complex model for the catalytic (de)hydrogenation step are in agreement with the previously reported outer sphere mechanism. These results support the further understanding of the mechanistic aspects behind the difference in reactivity of 1-heteroaryl substituted ethanols in comparison to reference substrates, as often referred to in the literature.

Izvorni jezik
Engleski

Znanstvena područja
Kemija

POVEZANOST RADA