Simplifying biomass conversion to valuable products with high efficiency is pivotal for the sustainable development of society. Herein, an efficient catalyst-free system using ammonia borane (AB) as the hydrogen donor is described, which enables controllable reaction selectivity towards four value-added products in excellent yield (82–100%) under very mild conditions. In particular, the system is uniquely
Probing the Mechanism of Photoaffinity Labeling by Dialkyldiazirines through Bioorthogonal Capture of Diazoalkanes
作者:Jessica G. K. O’Brien、Andrew Jemas、Papa Nii Asare-Okai、Christopher W. am Ende、Joseph M. Fox
DOI:10.1021/acs.orglett.0c02714
日期:2020.12.18
utilized for biological applications. For the fraction of intermolecular labeling that does involve a carbene mechanism, direct insertion is not necessarily involved, as products derived from a carbonylylide are also observed. We demonstrate that a strained cycloalkyne can intercept diazo compound intermediates and serve as a bioorthogonal probe for studying the contribution of the diazonium mechanism of
Efficient Conversion of Biomass Derived Levulinic Acid to γ‐Valerolactone Using Hydrosilylation
作者:Nitish K. Garg、Veronika Schmalz、Magnus T. Johnson、Ola F. Wendt
DOI:10.1002/ejoc.202100982
日期:2021.10.7
derived levulinic acid to γ-valerolactone using cost-effective silanes such as PMHS and TMDS and Lewis acid B(C6F5)3 as catalyst. This metal free methodology worked at roomtemperature reaching TONs and TOFs up to 16000 and 2000 h−1. Control experiments, kinetics, deuterium labelling and NMR studies were further performed to understand the reaction mechanism
在此,我们报告了一种有效的氢化硅烷化策略,使用具有成本效益的硅烷(例如 PMHS 和 TMDS)和路易斯酸 B(C 6 F 5)3作为催化剂,将木质纤维素生物质衍生的乙酰丙酸定量转化为 γ-戊内酯。这种无金属方法在室温下工作达到 TON 和 TOF,最高可达 16000 和 2000 h -1。进一步进行对照实验、动力学、氘标记和核磁共振研究以了解反应机理
Efficient catalytic hydrogenation of alkyl levulinates to γ-valerolactone
作者:Rosa Padilla、Mike S. B. Jørgensen、Márcio W. Paixão、Martin Nielsen
DOI:10.1039/c9gc01651a
日期:——
Efficient hydrogenations of neat alkyl levulinates to γ-valerolactone were achieved with low catalyst loadings of either PNP Ru or Ir complexes, respectively, in the presence of a small amount of a base at low temperature and H2 pressure. Quantitative conversions and TONs reaching 9300 were achieved. Furthermore, we demonstrate the feasibility of the system to perform several cycles. Finally, deuterium
Mechanistic Investigations into the Catalytic Levulinic Acid Hydrogenation, Insight in H/D Exchange Pathways, and a Synthetic Route to d<sub>8</sub>-γ-Valerolactone
作者:Qingqing Yuan、Henk H. van de Bovenkamp、Zhenlei Zhang、Anna S. Piskun、Selim Sami、Remco W.A. Havenith、Hero J. Heeres、Peter J. Deuss
DOI:10.1021/acscatal.1c02662
日期:2021.8.20
α-angelica lactone (α-AL). The insight provided by these studies revealed an as of yet unexploited sequential deuteration route to synthesize fully deuterated LA and GVL. The route starts by the conversion of LA to α-AL followed by a selectivedeuteration of the acidic protons of α-AL by H/D exchange with D2O. Subsequent ring-opening in D2O (d2-AL to d3-LA) and exchange of the remaining protons of d3-LA
γ-戊内酯 (GVL) 很容易通过碳水化合物衍生的乙酰丙酸 (LA) 的催化氢化获得,并且是一种有吸引力的生物基化学品,在化学品(例如,作为生物质衍生的溶剂)和运输燃料中都有广泛的应用部门。在这项研究中,我们使用同位素标记实验深入了解了在不同反应条件下将 LA 转化为 GVL 所涉及的催化氢化途径,使用水作为环境无害溶剂和 Ru/C 作为容易获得的催化剂。2结合量子化学计算的 H NMR 实验表明,氘原子可以在不同的位置结合,以及不同的中间体 4-羟基戊酸和 α-当归内酯 (α-AL) 的参与。这些研究提供的见解揭示了一种尚未开发的连续氘化途径来合成完全氘化的 LA 和 GVL。该路线首先将 LA 转化为 α-AL,然后通过与 D 2 O的 H/D 交换选择性氘化 α-AL 的酸质子。随后在 D 2 O 中开环(d 2 -AL 至 d 3 -LA) 和通过在 D 2 中加热通过酮-烯醇互变异构交换