The first enantioselective sequential phosphine-catalyzed (SPC as abbreviation) mode for the formation of tetrahydroquinolines with an ethynyl-substituted all-carbon quaternary stereogenic center is reported. In this SPC process, a novel [4 + 2] annulation process was devised employing α-substituted allenoates as C2 synthons (α–β′, 1,2-dipole) for the first time. 3-Ethynyl-substituted tetrahydroquinolines
Phosphine-Mediated Sequential [2+4]/[2+3] Annulation to Construct Pyrroloquinolines
作者:Junhui Lin、Yannan Zhu、Wei Cai、You Huang
DOI:10.1021/acs.orglett.1c04388
日期:2022.3.4
A domino [2+4]/[2+3] sequentialannulation reaction of MBH carbonates with N-unprotected indoles has been developed to provide various pyrroloquinoline derivatives in ≤94% yield and 20:1 dr. The reaction could be either mediated by stoichiometric PCy3 or catalyzed by R3PO via PIII/PV═O redox cycling in the presence of phenylsilane. This method assembles polycyclic 1,7-fused indoles in one step diastereoselectively
MBH 碳酸盐与 N-未保护的吲哚的多米诺 [2+4]/[2+3] 顺序环化反应已被开发,以提供≤94% 产率和 20:1 dr 的各种吡咯并喹啉衍生物。该反应可以由化学计量的 PCy 3介导,也可以由 R 3 PO 在苯基硅烷存在下通过 P III /P V = O 氧化还原循环催化。该方法一步非对映选择性地组装多环 1,7-稠合吲哚。
Enantioselective, Organocatalytic, Dissymmetric 1,4- and 1,2-Addition of Malononitrile to a Keto-bisenone Followed by an Oxa-Michael Addition Cascade
An unprecedented enantioselective dissymmetric 1,4- and 1,2-addition of malononitrile to a keto-bisenone followed by an oxa-Michael addition cascade to trap the in situ generated unstable tertiary alcohol have been developed. The quinine-derived amino-squaramide bifunctional organocatalyst worked efficiently and provides the oxa-spiro-[4,4]-nonanes in good yields and excellent diastereo- and enantioselectivities
One-Pot Synthesis of Cyclopropanes from Methylene Azabicyclo[3.1.0]hexanes Obtained by Formal Sequential [1+2]- and [2+3]-Cycloaddition Reaction of Prop-2-ynylsulfonium Salts and Tosylaminomethyl Enones
A formal sequential [1+2]‐ and [2+3]‐annulation of prop‐2‐ynylsulfonium salts and tosylaminomethyl enones was developed, constructing a series of methylene azabicyclo[3.1.0]hexanederivatives. A one‐pot procedure was established via hydration of an enamine intermediate to afford substituted cyclopropanes. Prop‐2‐ynylsulfonium salts acted as both C2 and C1 synthons in these two processes.
Recyclable Polymer Supported DMAP Catalyzed Cascade Synthesis of α-Pyrones
作者:Anshul Jain、Akanksha Kumari、Suman K. Saha、Khyati Shukla、Ashwani Chauhan、Ramesh K. Metre、Nirmal K. Rana
DOI:10.1021/acs.joc.3c01052
日期:2023.8.4
catalysts have emerged as one of the sustainable and cost-effective alternatives in organic synthetic chemistry. We have developed the first polymer-supported DMAP catalyzed one-pot synthesis of diversely substituted α-pyrones. The cascade approach involves C5 conjugate addition of 5H-oxazol-4-ones to α,β-unsaturated-β-ketoesters followed by lactonization/elimination.
聚合物负载的催化剂已成为有机合成化学中可持续且经济高效的替代品之一。我们开发了第一个聚合物支持的 DMAP 催化一锅法合成不同取代的 α-吡喃酮。级联方法涉及将 5 H -恶唑-4-酮与 α,β-不饱和-β-酮酯进行 C5 共轭加成,然后进行内酯化/消除。