Aldol Reaction of Aluminium Enolate Resulting from 1,4-Addition of R<sub>2</sub>AlX to α,β-Unsaturated Carbonyl Compound. A 1-Acylethenyl Anion Equivalent
Organoaluminium reagents R2AlX (X=SPh, SeMe) easily add to α,β-unsaturated carbonyl compounds in 1,4-fashion. The resulting aluminium enolates react with aldehydes to give aldol adducts in fair to good yields. Formal elimination of HX from the adducts provides α-substituted α,β-unsaturated carbonyl compounds. The overall transformation is an addition of aldehydes to 1-acylethenyl anion equivalent. Diethylaluminium iodide also is found to be an efficient reagent for the same type transformation.
Synthesis of Spiranes by Thiol-Mediated Acyl Radical Cyclization
作者:Day-Shin Hsu、Chih-Hao Chen、Chi-Wei Hsu
DOI:10.1002/ejoc.201501305
日期:2016.1
A general and efficient method for the preparation of spiro compounds is described. Various enone-aldehydes were exposed to t-dodecanethiol and AIBN at 75 °C in toluene to afford spirocyclic 1,4-diketones in moderate to good yields.
Samarium diiodide-mediated intramolecular cyclodimerisation of bis-α,β-unsaturated carbonyl compounds
作者:Jonathan R. Powell、Sally Dixon、Mark E. Light、Jeremy D. Kilburn
DOI:10.1016/j.tetlet.2009.03.031
日期:2009.7
Samarium(II) diiodide-mediated intramolecular cyclodimerisation of simple bis-enones and -enoates in THF/MeOH has been investigated. Spirocyclic and elaborated polycyclic products, including stereodefined cis-bicyclo[3.3.0]octane and trans-bicyclo[4.3.0]nonanes, are obtained in synthetically useful yield.
text] Treatment of formyl alpha,beta-enones with a TiCl(4)-R(4)NX combination induces an intramolecular aldolcyclization to furnish 2-acyl-3-halocyclohexanol with three controlled consecutive stereogenic centers. The reaction of bis-alpha,beta-enones with the combination provides cyclic diketones with high stereoselectivity via an intramolecular Michael addition reaction.
Spiranes synthesis based on samarium diiodide-mediated reductive cyclization
作者:Day-Shin Hsu、Chi-Wei Hsu
DOI:10.1016/j.tetlet.2012.02.068
日期:2012.4
A general and efficient method for the preparation of spiro compounds is described. Enone–aldehydes were exposed to samarium diiodide under mild conditions and various spirocyclic γ-hydroxyketones were obtained in good yields.