Unanticipated participation of HCl in nucleophilic chlorination reaction: expedient route to meta chlorophenols
摘要:
o-Quinone monoketals participated in a 1,4-addition reaction with HCl furnishing m-chlorophenols in high yields. Several readily available o-quinone monoketals were selected to display the generality of this serendipitous and unprecedented reaction and the results are presented herein. (C) 2015 Elsevier Ltd. All rights reserved.
Oxidations of substituted phenols with hypervalent iodine : Applications to the phthalide annulation route to anthraquinones
作者:Anthony S. Mitchell、Richard A. Russell
DOI:10.1016/0040-4039(93)85123-e
日期:1993.1
Substituted phenols are oxidized by phenyliodonium diacetate in methanol to yield either cyclohexa-2,4- or the isomeric 2,5-dienones depending upon the structure of the phenol. Annulation of these oxidation products with the anion of 3-cyanophthalide affords access to a range of anthraquinones not previously accessible by this route.
Oxidation with hypervalent iodine reagents. Part II: Novel cyclohexadienones as precursors for the synthesis of anthraquinones
作者:Anthony S. Mitchell、Richard A. Russell
DOI:10.1016/s0040-4020(97)00110-5
日期:1997.3
2,4-cyclohexadienones, 2,5-cyclohexadienones or mixtures of isomers, depending on the substrate being oxidized. Annulation of these cyclohexadienones with the anion of 3-cyanophthalide afforded anthraquinones in high yields.
o-benzoquinones, on reaction with nitrileoxides generated in situ from the corresponding hydroxamoyl chlorides, provide [3+2] cycloaddition products or novel isoxazoline derivatives through an unprecedented rearrangement. The isolated [3+2] cycloadducts could be transformed into the corresponding isoxazoline derivatives in the presence of Et3N and highlyfunctionalized benzisoxazoles in the presence
Cyclohexadienones participate in a two-step procedure, a Michael addition followed by aromatization, providing hitherto difficult-to-synthesize meta-functionalized phenol derivatives in good yield. Application of the developed approach is exemplified by synthesizing C-aryl acetophenones, C-aryl glycines, and elemicin - an allylphenol natural product.
[3+2] Cycloaddition of Masked o-Benzoquinones with Azomethine Ylides
A simple and efficient access to highly functionalized isoindolone derivatives via a [3+2] cycloaddition process between in situ generated azomethine ylides with various stable (isolable) masked o-benzoquinones is described. This approach allows a rapid and general synthesis of isoindolones with substituents to further manipulate and elaborate the structural complexity.