131376-11-9Relevant academic research and scientific papers
Cine substitution in 2-oxabicyclo[4.2.0]octanones and subsequent unusual rearrangements
Hassner, Alfred,Naidorf-Meir, Simha,Frimer, Aryeh A.
, p. 4051 - 4058 (1996)
Reaction of 2-chlorooxabicyclo[4.2.0]octanone 5 with several nucleophiles was examined and found to differ significantly from those of carbon analog 1. MeO- and PhS- led either to products of cine substitution 9 or of ring opening to cyclobutenones 8. With most enolates cine substitution occured via C-alkylation of the intermediate oxidoallyl cation in spite of formation of a new C-C bond between two quaternary carbons; with nitroalkanes O-alkylation was preferred. With azide as a nucleophile, further transformations occurred, among them an oxy-promoted electrocyclic cyclobutane opening, with incorporation of a phenyl triazole unit and final formation of the unusual product 19a. Evidence for a mechanism explaining formation of 19a was obtained by isolation of intermediates. Thermolysis or photolysis of 8e or 9b led via electrocyclic ring opening to a vinyl ketene which was trapped by MeOH, alkenes, dienes, or oxygen to produce polyfunctional unsaturated esters 29 and 30 or 8-membered ring lactone 31, fused cyclobutanones 33 and 34, pyranone 38, or γ-lactone 39, respectively.
UNUSUAL TRANSFORMATIONS IN OXABICYCLOOCTANONES. AN APPARENT OXY-PROMOTED ELCTROCYCLIC OPENING INVOLVING FUSED CYCLOBUTANOLS
Hassner, Alfred,Naidorf-Meir, Simha,Gottlieb, Hugo E.,Frolow, Felix
, p. 5669 - 5672 (2007/10/02)
Reaction of oxabicyclooctanone 3 with nucleophiles involves not only cine substitution but ring opening to cyclobutenones which are capable of further transformations.With azide as a nucleophile, further reactions occur, among them an oxy-promoted electrocyclic cyclobutane opening, with final formation of 8, the structure of which was verified by X-ray diffraction.
