Neighboring group participation in Lewis acid-promoted [3 + 4] and [3 + 5] annulations. The synthesis of oxabicyclo[3.n.1]alkan-3-ones
作者:Gary A. Molander、Kimberly O. Cameron
DOI:10.1021/ja00056a002
日期:1993.2
2-(alkoxycarbon)-m-oxabicyclo[3.n.1]alkan-3-ones can be constructed by this process in which two new carbon-carbon bonds are generated. Unusually high regioncontrol is observed, and good to excellent stereochemicalcontrol can be achieved at virtually every position on the new carbocycles. Intramolecular neighboringgroupparticipation is proposed to explain the unusually high selectivities attained in the annulation
cyclopentanols with three contiguous stereocenters were prepared with impressive diastereocontrol through a samarium diiodide induced 5-exo-trig radical process. The chiral unsaturated oxo ester precursors were prepared with ee values up to 90 % from propionaldehyde through a two-step organocatalyzed aldolization and Wittig–Horner olefination reaction sequence.
通过二碘化钐诱导的 5-exo-trig 自由基过程制备了具有三个连续立体中心的取代环戊醇,并具有令人印象深刻的非对映控制。通过两步有机催化醛醇化和 Wittig-Horner 烯化反应序列,由丙醛制备了 ee 值高达 90% 的手性不饱和羰基合成酯前体。
Carbene-catalyzed activation of cyclopropylcarbaldehydes for mannich reaction and δ-lactam formation: remote enantioselecitvity control and dynamic kinetic asymmetric transformation
作者:Jie Lv、Jun Xu、Xuling Pan、Zhichao Jin、Yonggui Robin Chi
DOI:10.1007/s11426-021-9989-1
日期:2021.6
An N-heterocyclic carbene (NHC)-catalyzed enantioselective Mannich reaction of the remote γ-carbon of cyclopropylcarbaldehydes is disclosed for the first time. Diastereo- and enantiomerically enriched multicyclic δ-lactam compound is afforded as the main product from 8 possible stereo-specific isomers through dynamickineticasymmetrictransformation (DYKAT) processes. Multiple chiral functional molecules
[EN] SYNTHESIS OF DEUTERATED ALDEHYDES<br/>[FR] SYNTHÈSE D'ALDÉHYDES DEUTÉRÉS
申请人:UNIV ARIZONA
公开号:WO2021045879A1
公开(公告)日:2021-03-11
Described are methods for preparing a deuterated aldehyde using N-heterocyclic carbene catalysts in a solvent comprising D2O. The methods may be used to convert a wide variety of aldehydes (e.g., aryl, alkyl, or alkenyl aldehydes) to C-1 deuterated aldehydes under mild reaction conditions without functionality manipulation.
Regiodivergent Radical Termination for Intermolecular Biocatalytic C–C Bond Formation
作者:Mark R. Petchey、Yuxuan Ye、Victor Spelling、James D. Finnigan、Samantha Gittings、Magnus J. Johansson、Martin A. Hayes、Todd K. Hyster
DOI:10.1021/jacs.4c00482
日期:2024.2.21
Radical hydrofunctionalizations of electronically unbiased dienes are challenging to render regioselective, because the products are nearly identical in energy. Here, we report two engineered FMN-dependent “ene”-reductases (EREDs) that catalyze regiodivergent hydroalkylations of cyclic and linear dienes. While previous studies focused exclusively on the stereoselectivity of alkene hydroalkylation,
电子无偏二烯的自由基氢官能化很难实现区域选择性,因为产物的能量几乎相同。在这里,我们报道了两种工程化的FMN依赖性“烯”还原酶(ERED),它们可以催化环状和线性二烯的区域差异加氢烷基化。虽然之前的研究主要集中在烯烃加氢烷基化的立体选择性上,但这项工作强调了 ERED 可以控制氢原子转移的区域选择性,从而提供了一种选择性制备结构异构体的方法,而使用传统合成方法很难制备这种异构体。从Gluconabacter sp. 中工程化 ERED。 (GluER) 提供了一种有利于 γ,δ-不饱和酮的变体,而来自商业 ERED 面板的工程变体则有利于 δ,ε-不饱和酮。有益突变的影响已通过底物对接研究和同位素标记实验探讨的机制进行了研究。各种α-溴酮可以与环状和直链二烯偶联。这些有趣的构建模块还可以进一步修改以生成难以获得的杂环化合物。