Intramolecular anodic olefin coupling reactions: the use of bis enol ether substrates
摘要:
In an effort to develop electrochemical methods for directly initiating oxidative cyclization reactions, the anodic oxidation of bis enol ether substrates has been examined. The reactions were found to lead to the formation of five-, six-, and seven-membered-ring 1,4-dicarbonyl equivalents. The reactions were not found to be useful for generating larger ring sizes. Both alkyl and silyl enol ether substrates were found to be compatible with the conditions required for carbon-carbon bond formation. Cyclic voltammetry studies indicated that the cyclizations were fast and that the reactions happened at or near the electrode surface. Finally, the cyclization reactions were shown to be compatible with the formation of quaternary carbons, even when carbon-carbon bond formation involved the generation of two vicinal quaternary carbons.
Bis(pyridine)iodonium Tetrafluoroborate (IPy2BF4): A Versatile Oxidizing Reagent
作者:José Barluenga、Francisco González-Bobes、Marcelo C. Murguía、Sreenivasa R. Ananthoju、José M. González
DOI:10.1002/chem.200400136
日期:2004.9.6
The use of bis(pyridine)iodoniumtetrafluoroborate (IPy(2)BF(4)) as an oxidizing agent towards different types of alcohols is reported. The observed reactivity involves different reaction pathways, as a function both of the structures of the starting materials and of the experimental conditions. Interestingly, the title iodine-containing compound is capable of a tuneable reaction with simple cycloalkanols
Synthesis of rigid hydrophobic tetrazoles using an Ugi multi-component heterocyclic condensation
作者:Hugues Bienaymé、K. Bouzid
DOI:10.1016/s0040-4039(98)00283-4
日期:1998.4
A highly convergent four-component, two-step, one-pot reaction between an aldehyde, a primary amine, an alkyl-β-(N,N-dimethylamino)-α-isocyanoacrylate and hydrazoic acid to form a substituted bicyclic tetrazole is disclosed. Vast arrays of small organic « drug-like å molecules can be combinatorially prepared with such transformation.
Water-Compatible Synthesis of 2-Trifluoromethyl-1,3-Dioxanes
作者:Liliana Becerra-Figueroa、Alexander F. Tiniakos、Joëlle Prunet、Diego Gamba-Sánchez
DOI:10.1002/ejoc.201801367
日期:2018.12.31
A water-compatible method for the diastereoselective synthesis of 2-trifluormethyl-1,3-dioxanes is described. The reaction proceeds under mild reaction conditions using simple inorganic bases; it has a very good substrate scope and can be performed with different Michael acceptors. Additionally, the reaction products can be further functionalized, showing an excellent perspective for future applications
Organocatalytic inter- and intramolecular [4+2] and [3+3] cycloadditions of α,β-unsaturatedaldehydes to give polysubstituted aromatic aldehydes are described. High periselectivity for the cycloadditions, with catalyst effects exerted by l-proline and pyrrolidine–HOAc, as well as cocatalyst, additive effects, has been observed.
A Direct Synthesis of Allenes by a Traceless Petasis Reaction
作者:Devon A. Mundal、Kelly E. Lutz、Regan J. Thomson
DOI:10.1021/ja301489n
日期:2012.4.4
A one-pot synthesis of allenes by the 2-nitrobenzenesulfonylhydrazide-mediated coupling of hydroxyaldehydes or ketones with alkynyl trifluoroborate salts is reported. This mild process involves in situ formation of a sulfonylhydrazone that reacts with alkynyl trifluoroborates to generate a transient propargylic hydrazide species. Decomposition of this unstable hydrazide via an intermediate monoalkyldiazine