A scalable, practical and general method for precise deuteration of aliphatic carboxylic acids via synergistic photoredox and HAT catalysis has been developed. The use of recirculation reactor achieved the preparative scale deuteration.
derived from bis(2-bromoallyl)amines undergo intramolecular carbometallation of a lithiateddouble bond, giving dilithiated dihydropyrroles. The cyclizations are promoted by N,N,N',N'-tetramethylethylenediamine (TMEDA). Reaction of these intermediates with electrophiles allows the preparation of some new fused and nonfused five-membered functionalized heterocycles. Although 2-lithioallylamines do
Mechanistic Studies of a Skatole-Forming Glycyl Radical Enzyme Suggest Reaction Initiation via Hydrogen Atom Transfer
作者:Beverly Fu、Azadeh Nazemi、Benjamin J. Levin、Zhongyue Yang、Heather J. Kulik、Emily P. Balskus
DOI:10.1021/jacs.1c13580
日期:2022.6.29
produced in the guts of swine and ruminants. Despite the importance of IAD, our understanding of its mechanism is limited. Here, we characterize the mechanism of Ou IAD, evaluating previously proposed hypotheses of: (1) a Kolbe-type decarboxylation reaction involving an initial 1-e– oxidation of the carboxylate of I3A or (2) a hydrogen atom abstraction from the α-carbon of I3A to generate an initial carbon-centered
氨基酸衍生的芳基乙酸酯的肠道微生物脱羧是一种化学上具有挑战性的酶促转化,它会产生影响宿主生理的小分子。来自Olsenella uli ( Ou IAD)的甘氨酰自由基酶 (GRE) 吲哚乙酸脱羧酶对 indole-3-acetate (I3A) 进行非氧化性自由基脱羧,产生粪臭素,这是一种在猪和反刍动物肠道中产生的与疾病相关的代谢物。尽管 IAD 很重要,但我们对其机制的理解是有限的。在这里,我们描述了Ou IAD 的机制,评估了先前提出的假设:(1)涉及初始 1-e 的 Kolbe 型脱羧反应-I3A 的羧酸盐的氧化或 (2) 从 I3A 的 α-碳中提取氢原子以产生初始的以碳为中心的自由基。定点诱变、动力学同位素效应实验、在 D 2 O 中进行的反应分析和计算建模与涉及初始氢原子转移的机制一致。这一发现更广泛地扩展了 GRE 脱羧酶和非氧化性脱羧酶所采用的自由基机制的类型。阐明 IAD