bioinsipred gold‐catalyzed tandem Diels–Alder/Diels–Alderreaction of an enynal and a 1,3‐diene, forming the highly‐strained benzotricyclo[3.2.1.02,7]octane skeleton, was reported. In contrast, a Diels–Alder/Friedel–Crafts tandem reaction occurred instead when silver salts were used as the catalyst. Although both reactions experienced the similar Diels–Alderreaction of a pyrylium intermediate with a
Aryne [3 + 2] cycloaddition with N-sulfonylpyridinium imides and in situ generated N-sulfonylisoquinolinium imides: a potential route to pyrido[1,2-b]indazoles and indazolo[3,2-a]isoquinolines
作者:Jingjing Zhao、Pan Li、Chunrui Wu、Hongli Chen、Wenying Ai、Renhong Sun、Hailong Ren、Richard C. Larock、Feng Shi
DOI:10.1039/c2ob06611d
日期:——
The aryne [3 + 2] cycloaddition process with pyridinium imides breaks the aromaticity of the pyridine ring. By equipping the imide nitrogen with a sulfonyl group, the intermediate readily eliminates a sulfinate anion to restore the aromaticity, leading to the formation of pyrido[1,2-b]indazoles. The scope and limitation of this reaction are discussed. As an extension of this chemistry, N-tosylisoquinolinium
与吡啶鎓酰亚胺的芳烃[3 + 2]环加成过程破坏了吡啶环的芳香性。通过在酰亚胺氮上加成磺酰基,该中间体容易消除亚磺酸根阴离子以恢复芳香性,从而导致吡啶并[1,2- b ]吲唑的形成。讨论了该反应的范围和局限性。作为该化学反应的扩展,通过AgOTf催化的6-endo-dig亲电环化反应从N '-(2-炔基亚苄基)-甲苯磺酰肼原位生成的N-甲苯磺酰异喹啉鎓亚胺易于进行芳烃[3 + 2]环加成反应而制得吲哚唑[3,2- a同一锅中的]-异喹啉,为这些潜在的抗癌药提供了高效途径。
Self-Relay Gold(I)-Catalyzed Pictet-Spengler/Cyclization Cascade Reaction for the Rapid Elaboration of Pentacyclic Indole Derivatives
Gold‐catalyzed cascadereactions allow the rapidelaboration of pentacyclic indolo[2,3‐a]quinolizidines from N‐allyl tryptamines and ortho‐alkynylarylaldehydes. The tandem process combines a gold‐catalyzed Pictet‐Spengler reaction and a cyclization occurring concomitantly with an allyl transfer from the nitrogen atom to the stilbene function. Various substituted allyls were successfully transferred
金催化的级联反应可快速合成N-烯丙基色胺和邻炔基芳基醛中的五环吲哚[2,3- a ]喹唑烷。串联过程结合了金催化的Pictet-Spengler反应和伴随从氮原子到二苯乙烯官能团的烯丙基转移而发生的环化反应。成功地转移了各种取代的烯丙基,从而提供了高非对映选择性的典型产物,产率为60-98%。带有丁烯醇链的色胺在高非对映选择性下会进一步环化成手性半胱氨酸。
A Mild and Regioselective Synthesis of α‐Fluoroketones
<i>via</i>
Gold and Selectfluor Partnership
作者:Xi Chen、Sophie Martini、Véronique Michelet
DOI:10.1002/adsc.201900268
日期:2019.8.5
from aldehyde‐yne and alkynylaryl ketone derivatives. Several functionalized and synthetically highly valuable α‐fluoroketones (21 compounds, up to 92%) were isolated in good to excellent yields via a remarkable regioselective oxyfluorination reaction in EtOH/H2O at room temperature. We have shed some light on parts of the mechanism by reacting diphenylacetylene and aldehyde‐yne with or without Selectfluor
通过从醛炔和炔基芳基酮衍生物开始的金与Selectfluor之间的卓有成效的结合,已开发出高效,温和且快速的α-氟代酮合成方法。通过在室温下在EtOH / H 2 O中进行显着的区域选择性氧氟化反应,可以分离出数种功能良好且合成价值很高的α-氟代酮(21种化合物,含量高达92%)。通过使二苯乙炔和乙炔与或不与Selectfluor进行反应,我们对机理的某些部分有所了解。该反应最有可能通过以下途径发生依次进行金催化的区域选择性水合,然后进行α-氟化反应,但是醛基的存在对于炔烃功能的反应性至关重要。氟酮被有效地转化为具有高度药用价值的4-氟异喹啉(9种化合物,占82%至95%)。
Metal-Free Decarboxylative Cyclization/Ring Expansion: Construction of Five-, Six-, and Seven-Membered Heterocycles from 2-Alkynyl Benzaldehydes and Cyclic Amino Acids
A one pot synthesis of 1H‐benzo[g]indoles, tetrahydrobenzo[h]quinolines, and naphtho[1,2‐b]azepines from 2‐alkynyl benzaldehydes and cyclic amino acids is reported. The salient feature of the strategy involves formation of three new bonds (one CN and two CC bonds) by a metal‐free decarboxylation/cyclization/one‐carbon ring expansion sequence in one pot.