High 1,2-Asymmetric Induction in Radical Reactions: Radical Addition to<i>γ</i>-Hydroxy<i>α</i>,<i>β</i>-Unsaturated Carboxylic Esters and Sulfones
作者:Katsuyuki Ogura、Akio Kayano、Motohiro Akazome
DOI:10.1246/bcsj.70.3091
日期:1997.12
High 1,2-asymmetric induction was realized by the addition of a 1-hydroxy-1-methylethyl radical to conformationally flexible (E)-γ-hydroxy α,β-unsaturated carboxylic esters and sulfones (1 and 2, respectively). Upon the irradiation (> 290 nm) of (E)-1 and benzophenone in 2-propanol, the 1-hydroxy-1-methylethyl radical was generated in situ and added to (E)-1 with high anti-stereoselectivity. The bulkier
temperature with malonates and acetoacetates in the presence of palladium-phosphine complexes as a catalyst to give γ-substituted α,β-unsaturated nitriles selectively. Also γ-acetoxy-α,β-unsaturated ester was attacked at y-position by malonate.
Aziridination of alkenes using 3-acetoxyaminoquinazolin-4(3H)ones: nucleophilic attack by the acetoxyamino group on ester-substituted allylic alcohols
作者:Robert S. Atkinson、John Fawcett、David R. Russell、Paul J. Williams
DOI:10.1039/c39940002031
日期:——
Allylic alcohols 5 and 7 and their acetates 6 and 8 are aziridinated using 3-acetoxyaminoquinazolinone 1; the preferred sense of diastereoselection in aziridination of 5 is inverted in aziridination of its acetate 6 whereas the preferred sense of diastereoselection from 7 is retained in aziridination of its acetate 8; this is interpreted as evidence for nucleophilic attack by the acetoxyamino nitrogen of 1 on the alkene with hydrogen bonding between the hydroxyl and N-acetoxy group present in aziridination of 5 but absent in the case of 7.
A novel synthetic method for γ-acetoxy-(E)-α,β-unsaturated esters by the palladium catalyzed regio- and stereoselective acetoxylation of β,γ-unsaturated esters
A new syntheticmethod for γ-acetoxy-α,β-unsaturatedesters by the acetoxylation of β,γ-unsaturatedesterscatalyzed by PdCl2 in the presence of KOAc and pentyl nitrite in acetic acid is presented. The reaction takes place at γ-position of the esters regioselectively with double bond migration to α,β-position. The E configuration of the double bond was confirmed by NMR analysis. Preliminary investigation
Nucleophilic substitution of tetracarbonyliron complexes of γ-acetoxycrotonates: The homologous Michael reaction
作者:J.R. Green、M.K. Carroll
DOI:10.1016/s0040-4039(00)92028-8
日期:1991.2
Iron tetracarbonyl complexes of γ-acetoxy-α,β-unsaturated esters react with silyl enol ethers in the presence of boron trifluoride-etherate to give substitution in the γ-position. The results are interpreted as being indicative of the intermediacy of a tetracarbonyliron-allyl cation complex which reacts at the terminus remote from the ester function.