Abstract:Oxadisilole‐fused benzisoxazoles or naphthisoxazoles were obtained through 1,3‐dipolar cycloaddition of arynes with nitrile oxides in good yields at room temperature. Key to the procedure is the simultaneous in situ generation of reactive nitrile oxides from arenecarbohydroximoyl chlorides and aryne reactants from benzobis(oxadisilole) or 2,3‐naphthoxadisilole. One oxadisilole‐fused benzisoxazole is a new precursor of a benzyne formed by a phenyliodination/fluoride‐induced elimination protocol. By using this b… Show more
“…13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 163.8, 156.2, 136.3, 129.9, 129.4, 129.2, 127.3, 124.0, 121.8, 120.1, 110.2. The spectroscopic data are in agreement with those previously reported …”
Section: Experimental
Sectionsupporting
confidence: 93%
“…Column chromatography on silica gel (eluent: petroleum ether:ethyl acetate = 20:1) followed by washing with pentane afforded the title product in 53% yield (484.5 mg) as a light yellow solid). 1 22 3-(2-Methoxyphenyl)benzo [d]isoxazole (2d). Method A was used.…”
Benzo[d]isoxazoles
are found to act as novel nucleophiles
to undergo gold-catalyzed [5 + 1] or [5 + 2] cycloaddition reactions
with ynamides. The reaction provides a concise and chemoselective
access to polysubstituted 2H-benzo[e][1,3]oxazines or benzo[f][1,4]oxazepines. In addition,
benzo[d]isoxazoles can also react with gold-carbene
intermediates derived from propargyl esters to afford [5 + 1] annulation
products.
“…13 C{ 1 H} NMR (100 MHz, CDCl 3 ) δ 163.8, 156.2, 136.3, 129.9, 129.4, 129.2, 127.3, 124.0, 121.8, 120.1, 110.2. The spectroscopic data are in agreement with those previously reported …”
Section: Experimental
Sectionsupporting
confidence: 93%
“…Column chromatography on silica gel (eluent: petroleum ether:ethyl acetate = 20:1) followed by washing with pentane afforded the title product in 53% yield (484.5 mg) as a light yellow solid). 1 22 3-(2-Methoxyphenyl)benzo [d]isoxazole (2d). Method A was used.…”
Benzo[d]isoxazoles
are found to act as novel nucleophiles
to undergo gold-catalyzed [5 + 1] or [5 + 2] cycloaddition reactions
with ynamides. The reaction provides a concise and chemoselective
access to polysubstituted 2H-benzo[e][1,3]oxazines or benzo[f][1,4]oxazepines. In addition,
benzo[d]isoxazoles can also react with gold-carbene
intermediates derived from propargyl esters to afford [5 + 1] annulation
products.
“…In addition to the methods described above, Tokiwa and Arai reported a single example of the synthesis of a 1,2‐benzoisoxazole via [3+2] cycloaddition using silicon as a regioselectivity controlling element (Scheme ) 58. The Cheng group investigated the synthesis of oxadisilole‐fused 1,2‐benzoisoxazoles via [3+2] cycloaddition of benzynes generated by the phenyliodination/elimination protocol (not shown) 59…”
Section: Synthesis Of Isoxazoles Via [3+2] Cycloaddition Reactionsmentioning
The synthesis of new β‐cyclodextrin dimers linked through their primary faces by different glycerol‐like moieties by click chemistry is described. The unusual behaviour of these cyclodextrin–glycerol dimers in aqueous solution has been studied by NMR spectroscopy. We show that, depending on the length of the linking arm between the two cyclodextrins, the dimers could adopt very different conformations in water: symmetrical or pseudo[1]rotaxane‐like structures through one D‐glucopyranose unit tumbling in one β‐cyclodextrin.
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