Synthesis and Study of Oxadisilole‐Fused Benzisoxazoles or Naphthisoxazoles

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 benzyne, cycloadducts were synthesized in good yields. The de‐oxadisilole reaction of some of the oxadisilole‐fused benzisoxazoles could be easily conducted with a 1.0 M solution of tetrabutylammonium fluoride in THF at room temperature.

Selective [5 + 1] and [5 + 2] Cycloaddition of Ynamides or Propargyl Esters with Benzo[d]isoxazoles via Gold Catalysis

“…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 …”

“…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.…”

β‐Cyclodextrin–Glycerol Dimers: Synthesis and NMR Conformational Analysis

“…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…”