格氏试剂在手性过氢吡啶并[ 2,1- b ]吡咯并[1,2- d ] [1,3,4]恶二嗪上路易斯酸介导的S N 2型置换。非对称合成2-取代哌啶的手性诱导
摘要:
用格氏试剂在手性过氢吡啶并[ 2,1 - b ]吡咯并[1,2- d ] [1,3,4]恶二嗪上进行Et 2 AlCl介导的亲核烷基化反应是在低温下通过S N 2机理进行的(低于-80°C)时具有很高的反演立体选择效果,而在升高的温度下会优先生成离子,从而导致保持性立体选择。该方法学为2-取代的哌啶的对映选择性的制备提供了有用的途径,并且用于(+)-亚氨酸的不对称合成。
Studies in biomimetic alkaloid syntheses. 6. Alternative pathways to secodines and their acyclic enamino acrylate analogs. Total syntheses of desethylibophyllidine, D-norvincadifformine, desethylvincadifformine, 20-methyldesethylvincadifformine, and 3-oxovincadifformine
SN1-Type Reactions in the Presence of Water: Indium(III)-Promoted Highly Enantioselective Organocatalytic Propargylation of Aldehydes
作者:Riccardo Sinisi、Maria Victoria Vita、Andrea Gualandi、Enrico Emer、Pier Giorgio Cozzi
DOI:10.1002/chem.201100729
日期:2011.6.27
Water under troubled chemistry! The first catalytic stereoselective addition of aldehydes to internal functionalized propargylic alcohols promoted by a combination of organocatalysis and indium triflate is described (see scheme). The reaction is tolerant of functional groups (FG) and was performed in the presence of water. High enantioselectivities (anti, 92–99 % ee) and moderate diastereomeric ratios
The present invention relates to novel 3-azabicyclo[3.2.2]nonane derivatives of the general formula (I)
or a pharmaceutically acceptable salt thereof
wherein R1, R2, R3, R4, R5, R6, R7, R8, R9 and R10 are as defined in the specification. The novel 3-azabicyclo[3.2.2]nonane derivatives are particularly useful for treatment and prevention of malaria and trypanosomiasis.
Catalytic Hydroetherification of Unactivated Alkenes Enabled by Proton‐Coupled Electron Transfer
作者:Elaine Tsui、Anthony J. Metrano、Yuto Tsuchiya、Robert R. Knowles
DOI:10.1002/anie.202003959
日期:2020.7.13
We report a catalytic, light‐driven method for the intramolecular hydroetherification of unactivated alkenols to furnish cyclic ether products. These reactions occur under visible‐light irradiation in the presence of an IrIII‐based photoredox catalyst, a Brønsted base catalyst, and a hydrogen‐atom transfer (HAT) co‐catalyst. Reactive alkoxy radicals are proposed as key intermediates, generated by direct
我们报告了一种催化光驱动方法,用于未活化烯醇的分子内加氢醚化以提供环醚产品。这些反应在 Ir III基光氧化还原催化剂、布朗斯台德碱催化剂和氢原子转移 (HAT) 助催化剂存在下在可见光照射下发生。反应性烷氧基被认为是关键中间体,是通过质子耦合电子转移机制直接均裂激活醇 O−H 键而产生的。该方法表现出广泛的底物范围和高官能团耐受性,并且适应多种烯烃取代模式。还提出了证明该催化系统扩展到碳醚化反应的结果。
Highly Enantioselective α Alkylation of Aldehydes with 1,3-Benzodithiolylium Tetrafluoroborate: A Formal Organocatalytic α Alkylation of Aldehydes by the Carbenium Ion
作者:Andrea Gualandi、Enrico Emer、Montse Guiteras Capdevila、Pier Giorgio Cozzi
DOI:10.1002/anie.201102562
日期:2011.8.16
A formal formyl: The organocatalytic stereoselective addition of formyl equivalents to aldehydes (see scheme) tolerates a large variety of functional groups to afford products with high enantioselectivity (92–97 % ee) and good yields (up to 95 %). The benzodithiol group can be easily removed with Raney Ni or metalated with nBuLi, thus giving access to a methyl group or to a wide range of useful intermediates
Regio- and <i>Trans</i>-Selective Ni-Catalyzed Coupling of Butadiene, Carbonyls, and Arylboronic Acids to Homoallylic Alcohols under Base-Free Conditions
作者:Yu-Qing Li、Guang Chen、Shi-Liang Shi
DOI:10.1021/acs.orglett.1c00488
日期:2021.4.2
We herein report a Ni-catalyzed three-component coupling of 1,3-butadiene, carbonylcompounds, and arylboronic acids as a general synthetic approach to 1,4-disubstituted homoallylic alcohols, an important class of compounds, which have previously not been straightforward to access. The reaction occurs efficiently using a Ni(cod)2 catalyst without any external base and ligand at ambient temperature