Palladium(II)-Catalyzed Synthesis of Functionalized Indenes from o-Alkynylbenzylidene Ketones
摘要:
An efficient method for the synthesis of functionalized indenes from o-alkynylbenzylidene ketones under palladium(II) catalysis was developed. The reaction is initiated by trans-nucleopalladation of alkynes, followed by conjugate addition and quenched by protonolysis of the carbon palladium bond. With acetate and halide ions as nucleophiles, 3-acetoxy- and 3-halogen-substituted indenes could be obtained in high yields.
Stereocontrolled synthesis of oxygen-bridged polycycles via intermolecular [3+2] cyclization of platinum-bound pyrylium with alkenes
作者:Chang Ho Oh、Hyun Jik Yi、Ji Ho Lee、Dong Hee Lim
DOI:10.1039/c001495h
日期:——
2-(3-Benzyloxy)prop-1-ynyl)benzaldehyde with PtCl(2) in toluene would form Pt-pyryliums that underwent [3+2] cycloaddition with alkenes to the oxygen-bridged (5H-benzo[7]annulen-5-ylidene)platinum(ii) intermediates with good stereoselectivities. Their tandem rearrangement afforded diverse types of polycycles depending on the electronic nature of the alkenes.
Concise Synthesis of 1,2-Dihydroisoquinolines and 1<i>H</i>-Isochromenes by Carbophilic Lewis Acid-Catalyzed Tandem Nucleophilic Addition and Cyclization of 2-(1-Alkynyl)arylaldimines and 2-(1-Alkynyl)arylaldehydes
By using carbophilic Lewisacids, In(OTf)3, NiCl2, and AuCl(PPh3)/AgNTf2, a concise and efficient synthesis of 1,3-disubstituted 1,2-dihydroisoquinolines has been achieved via tandem nucleophilic addition and cyclization of 2-(1-alkynyl)arylaldimines. Addition of proton sources such as water, CF3CH2OH, and 2,6-di-tert-butyl-4-methoxyphenol was essential for the Lewis acid-catalyzed tandem reactions
1,3-Dipolar cycloaddition of 4-platinumisochromenyliums with an olefin and tandem insertion into benzylic C–H bonds
作者:Ji Hee Kim、Devalina Ray、Chang Seop Hong、Jin Wook Han、Chang Ho Oh
DOI:10.1039/c3cc42525h
日期:——
Isochromenylium-4-ylplatinum(II) species, generatedfrom 1-(2-alkynylphenyl)hex-5-en-1-ones and Pt(II), reacted with a pendant olefin via [3+2] cycloaddition to form tetracyclic Pt-carbene complexes, which underwent C-H insertion with a benzyloxy group at delta or epsilon positions to give highly complex polycycles, which are otherwise hard to access.
Novel Platinum-Catalyzed Tandem Reaction: An Efficient Approach to Construct Naphtho[1,2-<i>b</i>]furan
作者:Hao Wei、Hongbin Zhai、Peng-Fei Xu
DOI:10.1021/jo802645s
日期:2009.3.6
An efficient approach to synthesize naphtho[1,2-b]furan has been developed via platinum-catalyzedtandem reaction. This new tandem catalysis induces a cycloisomerization of allenyl ketone, followed by a 6π-electrocyclization-type reaction of carbene intermediate. The metal carbene proved to be an effective intermediate in the 6π-electrocyclization-type reaction.
通过铂催化串联反应,已经开发了一种合成萘并[1,2- b ]呋喃的有效方法。这种新的串联催化作用引起烯丙基酮的环异构化,然后进行卡宾中间体的6π-电环化型反应。金属卡宾被证明是6π-电环化型反应的有效中间体。
Gold Carbenes from Substituted Propargyl Acetates: Intramolecular Ene-type Reactions to 2-Acetoxynaphthalene Derivatives
作者:Chang Ho Oh、Ji Hee Kim、Lanhua Piao、Jin Yu、So Young Kim
DOI:10.1002/chem.201301384
日期:2013.8.5
A new Au‐catalyzed cascade reaction was developed for the conversion of propargylic acetates 1 to benzannulated products 2 in good to excellent yields. The gold catalyst is involved in generating intermediate A and in the ene‐typereaction of intermediate B for the formation of product 2 (see scheme).