119367-65-6Relevant academic research and scientific papers
Divergent Access to Seven/Five-Membered Rings Based on [1,6]-Hydride Shift/Cyclization Process
Hoshino, Daiki,Mori, Keiji
, p. 9403 - 9407 (2021/12/14)
We have achieved a divergent access to seven/five-membered rings based on a [1,6]-hydride shift/cyclization process from benzylidenemalonate with an o-alkoxymethyl group. Whereas Yb(OTf)3 afforded benzoxepines (with a seven-membered ring) selectively, indanes (with a five-membered ring) were the main products when Sc(OTf)3 was employed.
Intramolecular Generation of Oxonium Ylides from Functionalized Arylcarbenes
Kirmse, Wolfgang,Kund, Klaus
, p. 1465 - 1473 (2007/10/02)
Arylcarbenes carrying alkoxyalkyl groups in the ortho position have been generated by flash pyrolysis and photolysis of appropriate tosylhydrazone sodium salts.In the gas phase and in a aprotic solvents, interaction of the carbenes with the lone electron pairs of oxygen competes efficiently with insertion into C-H bonds.Both five- and six-membered cyclic oxonium ylides have been generated.The ylides 23, 37, 61b, and 74 undergo 1,2 shifts of benzyl groups with ease, even if ring contraction to highly strained benzocyclobutenes is involved (23, 74).The oxonium ylides37 and 61b strongly prefer the nonconcerted Stevens rearrangement to the sigmatropic Sommelet rearrangement, in contrast to analogous ammonium ylides.Alkyl shifts occur to a very minor extent, if at all.Evidence is presented that alcohols intercept both the carbenes and the oxonium ylides.Protonation of the ylides leads to cyclic oxonium ions, which undergo nucleophilic cleavage of the C-O bonds.Acid catalyzed decomposition of the appropriate diazo compounds gives rise to six-membered, but not to five-membered, cyclic oxonium ions, thus confirming the different intramolecular reactivities of arylcarbenes and benzyl cations.The efficiency of carbene interception increases with increasing acidity of the medium, suggesting nucleophilic behavior (protonation) of the arylcarbenes.
INTRAMOLECULAR CYCLIZATIONS OF HANTZSCH 1,4-DIHYDROPYRIDINES: SYNTHESIS OF DI- AND TETRAHYDROINDENOPYRIDINES
Young, Steven D.,King, Stella W.,Remy, David C.
, p. 3081 - 3083 (2007/10/02)
Hantzsch 4-phenyl-1,4-dihydropyridines bearing electrophilic ortho substituents react with trimethylsilyl cyanide/zinc iodide or base resulting in an intramolecular cyclization reaction to give di-and tetrahydroindenopyridines in good yield.
