Two-step Synthesis of New γ-Lactones via Cyclization of 7-Chloro-2-(methoxycarbonyl)-4-6-dimethylocta-(2<i>E</i>,4<i>E</i>,6<i>E</i>)-trienoic acid
作者:Jean-Marc Dillenschneider、Laurent Dufossé、Mireille Fouillaud、Nuthathai Sutthiwong、Roger Labia、Alain Valla
DOI:10.1002/jhet.2444
日期:2016.9
A new rapid synthesis of γ‐lactones, cis fused with a cyclopentenic ring by thermal cyclization of 7‐chloro‐2‐(methoxycarbonyl)‐4‐6‐dimethylocta‐7‐phenyl (or methyl) (2E,4E,6E)‐trienoic acids was reported. The key step implicates an intramolecular cyclization to a cyclopentenyl cation, according to an electrocyclic π2s + π2a conrotatory process, published in a recent paper (from the corresponding diacids)
A Straightforward Approach toward Multifunctionalized Pyridazines via Imination/Electrocyclization
作者:Alexander V. Komkov、Anna S. Komendantova、Leonid G. Menchikov、Elena I. Chernoburova、Yulia A. Volkova、Igor V. Zavarzin
DOI:10.1021/acs.orglett.5b01718
日期:2015.8.7
A facile synthesis of functionalized 3-carbamide pyridazines starting from readily available chlorovinyl aldehydes and oxamic acid thiohydrazides via cascade imination/electrocyclization is reported. In the presence of p-toluenesulfuric acid, various ketones have been efficiently incorporated into the pyridazine derivatives through a two-step sequence involving a VilsmeierHaack reaction and imination. The synthetic value of this method has been demonstrated by efficient synthesis of steroidal pyridazines.
On the Regio and Stereo Selective Formylations of Acyclic Alpha Methylene Ketones towards Vilsmeier Haack Reagent
作者:Arindam Chakraborty、Jayanta K. Ray
DOI:10.1080/00397919508015433
日期:1995.6
The regio and stereo selectivities of Vilsmeier Haack reaction of ketomethylene compounds have been predicted. The possible mechanistic pathway has also been proposed.