Rhodium-Catalyzed Room Temperature C–C Activation of Cyclopropanol for One-Step Access to Diverse 1,6-Diketones
摘要:
A rhodium-catalyzed room temperature C-C activation of cyclopropanol has been demonstrated for the single-step synthesis of a range of electronically and sterically distinct 1,6-diketones. This reaction proceeds efficiently in shorter reaction time following a highly atom-economical pathway. To illustrate the synthetic potential of 1,6-diketones, aldol and macrocyclization reactions have been successfully demonstrated. Preliminary mechanistic studies revealed the involvement of nonradical pathways.
Previous transition metal-catalyzed synthesis processes of δ-diketones are plagued by the high cost of the rhodium catalyst and harsh reaction conditions. Herein a low-cost, roomtemperature ruthenium catalytic method is developed based on the coupling of α-keto sulfoxoniumylides with cyclopropanols. The mild protocol features a broad substrate scope (47 examples) and a high product yield (up to 99%)
Iron-Catalyzed Ring Opening of Cyclopropanols and Their 1,6-Conjugate Addition to <i>p</i>-Quinone Methides
作者:Baliram B. Mane、Suresh B. Waghmode
DOI:10.1021/acs.joc.1c02059
日期:2021.12.17
A novel iron-catalyzed ringopening of cyclopropanols and their 1,6-conjugate addition to p-quinone methides for accessing substituted phenols is disclosed. In this protocol, various cyclopropanols are converted to alkyl radicals and undergo 1,6-conjugate addition to p-quinone methides toward C–C bond formation. The salient features of this methodology include operationally simple and mild reaction
Silver-Catalyzed Ring-Opening Strategy for the Synthesis of β- and γ-Fluorinated Ketones
作者:Huijun Zhao、Xuefeng Fan、Jiajia Yu、Chen Zhu
DOI:10.1021/jacs.5b00939
日期:2015.3.18
A regioselective synthesis of β- and γ-fluorinated ketones via silver-catalyzed ring opening is described. A variety of β- and γ-fluorinated ketones are efficiently prepared, respectively, from tertiary cyclopropanol and cyclobutanol precursors, providing a straightforward approach for the introduction of a fluorine atom into complex molecules. Preliminary mechanistic studies suggest that a radical-mediated
描述了通过银催化开环的 β- 和 γ-氟化酮的区域选择性合成。各种β-和γ-氟化酮分别由叔环丙醇和环丁醇前体有效制备,为将氟原子引入复杂分子提供了一种直接的方法。初步机理研究表明,涉及自由基介导的连续 CC 键裂解和 CF 键形成途径。
ProPhenol Derived Ligands to Simultaneously Coordinate a Main‐Group Metal and a Transition Metal: Application to a Zn−Cu Catalyzed Reaction
作者:Barry M. Trost、Guoting Zhang、Minghao Xu、Xiaotian Qi
DOI:10.1002/chem.202104268
日期:2022.2.16
A new bi-functional ligandbearingchiralN-heterocycliccarbene (NHC) and prolinol moieties is designed and applied in the generation of a Cu/Zn hetero-bimetallic complex, which unlocks the asymmetric allylic alkylation reactions of allyl phosphates with zinc keto-homoenolates generated from cyclopropanols, leading to the formation of various γ-vinyl ketones with good regio- and enantio-selectivity
设计了一种新的带有手性 N-杂环卡宾(NHC) 和脯氨醇部分的双功能配体,并应用于生成 Cu/Zn 杂双金属配合物,从而解锁了磷酸烯丙酯与酮基高烯醇锌的不对称烯丙基烷基化反应由环丙醇生成,导致形成具有良好区域选择性和对映选择性的各种 γ-乙烯基酮。DFT 计算支持烯丙基磷酸酯与催化剂的螯合促进了 S N 2' 的添加,并且配体-底物空间相互作用解释了立体选择性结果。
Uracil-Cu(<scp>i</scp>) catalyst: allylation of cyclopropanols with Morita–Baylis–Hillman alcohols under water-tolerant conditions
a uracil-copper catalytic system was developed to promote ring-opening allylation of cyclopropanols with allylic alcohols under water-tolerant conditions. A new C–OH bond-breaking model can well resolve the trade-off between the need for acidic activators for C(allyl)–OH bond cleavage and the demand for strong basic conditions for generating homoenolates. Therefore, Morita–Baylis–Hillman alcohols,
受铜与 DNA 和 RNA 的高亲和力的启发,开发了尿嘧啶-铜催化系统,以促进环丙醇与烯丙醇在耐水条件下的开环烯丙基化。一种新的C-OH键断裂模型可以很好地解决C(烯丙基)-OH键断裂所需的酸性活化剂与生成同烯醇盐所需的强碱性条件之间的权衡。因此,Morita-Baylis-Hillman 醇,而不是它们的预活化版本,可以直接掺入与环丙醇的脱水交叉偶联中,产生水作为唯一的副产物。多种功能化的δ 、 ε-不饱和酮以良好到高的收率和高E-选择性获得。