629-41-4Relevant articles and documents
Multi-enzymatic cascade reactions with Escherichia coli-based modules for synthesizing various bioplastic monomers from fatty acid methyl esters?
Jung, Hyunsang,Kim, Byung-Gee,Kim, Ye Chan,Park, Beom Gi,Patil, Mahesh D.,Sarak, Sharad,Yoo, Hee-Wang,Yun, Hyungdon
supporting information, p. 2222 - 2231 (2022/04/03)
Multi-enzymatic cascade reaction systems were designed to generate biopolymer monomers using Escherichia coli-based cell modules, capable of carrying out one-pot reactions. Three cell-based modules, including a ω-hydroxylation module (Cell-Hm) to convert fatty acid methyl esters (FAMEs) to ω-hydroxy fatty acids (ω-HFAs), an amination module (Cell-Am) to convert terminal alcohol groups of the substrate to amine groups, and a reduction module (Cell-Rm) to convert the carboxyl groups of fatty acids to alcohol groups, were constructed. The product-oriented assembly of these cell modules involving multi-enzymatic cascade reactions generated ω-ADAs (up to 46 mM), α,ω-diols (up to 29 mM), ω-amino alcohols (up to 29 mM) and α,ω-diamines (up to 21 mM) from 100 mM corresponding FAME substrates with varying carbon chain length (C8, C10, and C12). Finally 12-ADA and 1,12-diol were purified with isolated yields of 66.5% and 52.5%, respectively. The multi-enzymatic cascade reactions reported herein present an elegant ‘greener’ alternative for the biosynthesis of various biopolymer monomers from renewable saturated fatty acids.
Erbium-Catalyzed Regioselective Isomerization-Cobalt-Catalyzed Transfer Hydrogenation Sequence for the Synthesis of Anti-Markovnikov Alcohols from Epoxides under Mild Conditions
Liu, Xin,Longwitz, Lars,Spiegelberg, Brian,T?njes, Jan,Beweries, Torsten,Werner, Thomas
, p. 13659 - 13667 (2020/11/30)
Herein, we report an efficient isomerization-transfer hydrogenation reaction sequence based on a cobalt pincer catalyst (1 mol %), which allows the synthesis of a series of anti-Markovnikov alcohols from terminal and internal epoxides under mild reaction conditions (≤55 °C, 8 h) at low catalyst loading. The reaction proceeds by Lewis acid (3 mol % Er(OTf)3)-catalyzed epoxide isomerization and subsequent cobalt-catalyzed transfer hydrogenation using ammonia borane as the hydrogen source. The general applicability of this methodology is highlighted by the synthesis of 43 alcohols from epoxides. A variety of terminal (23 examples) and 1,2-disubstituted internal epoxides (14 examples) bearing different functional groups are converted to the desired anti-Markovnikov alcohols in excellent selectivity and yields of up to 98%. For selected examples, it is shown that the reaction can be performed on a preparative scale up to 50 mmol. Notably, the isomerization step proceeds via the most stable carbocation. Thus, the regiochemistry is controlled by stereoelectronic effects. As a result, in some cases, rearrangement of the carbon framework is observed when tri-and tetra-substituted epoxides (6 examples) are converted. A variety of functional groups are tolerated under the reaction conditions even though aldehydes and ketones are also reduced to the respective alcohols under the reaction conditions. Mechanistic studies and control experiments were used to investigate the role of the Lewis acid in the reaction. Besides acting as the catalyst for the epoxide isomerization, the Lewis acid was found to facilitate the dehydrogenation of the hydrogen donor, which enhances the rate of the transfer hydrogenation step. These experiments additionally indicate the direct transfer of hydrogen from the amine borane in the reduction step.
Robust cobalt oxide catalysts for controllable hydrogenation of carboxylic acids to alcohols
Song, Song,Wang, Dong,Di, Lu,Wang, Chuanming,Dai, Weili,Wu, Guangjun,Guan, Naijia,Li, Landong
, p. 250 - 257 (2018/02/20)
The selective catalytic hydrogenation of carboxylic acids is an important process for alcohol production, while efficient heterogeneous catalyst systems are still being explored. Here, we report the selective hydrogenation of carboxylic acids using earth-abundant cobalt oxides through a reaction-controlled catalysis process. The further reaction of the alcohols is completely hindered by the presence of carboxylic acids in the reaction system. The partial reduction of cobalt oxides by hydrogen at designated temperatures can dramatically enhance the catalytic activity of pristine samples. A wide range of carboxylic acids with a variety of functional groups can be converted to the corresponding alcohols at a yield level applicable to large-scale production. Cobalt monoxide was established as the preferred active phase for the selective hydrogenation of carboxylic acids.
