o-Xylylenes and isoindenes as reaction intermediates

Abstract

After being largely ignored for many years, the simple structures o-xylylene (1) and isoindene (2) (also called o-quinodimethanes) and their derivatives are now under active investigation from theoretical, physical, physical organic, and synthetic organic viewpoints.The earliest report in which an o-xylylene structure was implicated was the reaction of , , ', '-tetrabromo-o-xylene with iodide ion to give 1,2-dibromobenzocyclobutene.1,2 This assignment was confirmed

Fluorinated Furan‐2(5H)‐ones: Reactivity and Stereoselectivity in Diels–Alder Reactions

“…[23] Also in our case, the reactions of all fluorinated furan-2(5H)-ones 1-4 with this diene were successful (Scheme 2). The reaction between 3-fluorofuran-2(5H)-one (1) and this diene in toluene at 130°C in a sealed tube for 1 day gave a 22:78 mixture of two diastereomeric cycloadducts 5 and 6.…”

The First Benzo[1,2:4,5]dicyclobutenones and Their Tricarbonylchromium Complexes

“…In addition, 6 -unlike 2-iodotosylarenes [15] -is commercially available. Treatment of Hydrolysis of the diacetals 8 and 9 with 50 % HCl/THF (1:1) at reflux for 5 h afforded unprotected 2,7-dimethoxytricyclo[6.2.0.0 3,6 ]deca-1,3(6),7-triene-4,10-dione (15) and 2,7-dimethoxytricyclo[6.2.0.0 3,6 ]deca-1,3(6),7-triene-4,9-dione (16), the first diketones derived from 3 and 4, in 88 % and 89 % yields, respectively.…”

“…Tricarbonyl{2,7-dimethoxytricyclo[6.2.0.0 3,6 ]deca-1(8),2,6-triene-4,9-dione}chromium(0) (20): Formic acid (150 mL) was added to 19 (4.0 g, 9.0 mmol) at 0°C in the dark. The mixture was stirred for 2 h at 25°C, becoming brown.…”

ortho-Quinodimethane from anthracene epidioxide: Scope of the Diels–Alder reaction and mild preparation of naphthalene derivatives

“…They were originally obtained by the double elimination of a,a 0 -dibromo-ortho-xylenes [1] or by thermal opening of the corresponding benzocyclobutenes [2,3], and several reviews emphasised the importance of these transients as tools for the synthesis of cyclic organic compounds [4][5][6][7][8][9]. An interesting reaction was the direct formation of the naphthalene derivatives 2 by Diels-Alder reaction with dibromo-ortho-xylylene 1 (generated from tetrabromoxylene) with spontaneous loss of HBr [1,10,11] (Scheme 1).…”