Seven-membered heterocycles. 9. Synthesis and properties of some 5-alkyl and 5-aryl derivatives of 1-benzothiepin

Tunable Synthesis of Pyrazolo Oxepines, Pyrazolo Thiophenes and 1H‐Indazoles Using Alkylation, Aldol Condensation and Thermal Rearrangement

“…Pyrazolothiepine under thermal conditions rearranges with the elimination of sulfur to give 1 H indazoles. A similar thermal rearrangement of benzo thiepienes to naphthalenes has been reported in the literatures as 1‐benzothiepines are less stable and they tend to rearrange to thermally stable naphthalenes [15–17] …”

“…A similar thermal rearrangement of benzo thiepienes to naphthalenes has been reported in the literatures as 1benzothiepines are less stable and they tend to rearrange to thermally stable naphthalenes. [15][16][17] Our next effort was to screen different bases for the formation of compounds 8 a and 9 a. The observations are tabulated in Table 2.…”

Rapid Access to Halohydrofurans via Brønsted Acid-Catalyzed Hydroxylation/Halocyclization of Cyclopropyl Methanols with Water and Electrophilic Halides

“…On the basis of these earlier studies, we reasoned that a synthetic approach to 3-halohydrofurans could be achieved through NXS or Selectfluor-mediated cyclization of a homoallylic alcohol formed in situ from Brønsted acid-catalyzed hydroxylative ring-opening of cyclopropyl methanols. While Brønsted acid-mediated reactions of alcohol pro-electrophiles have come under increasing scrutiny, − to our knowledge those that make use of cyclopropyl methanols have thus far been limited to works describing the synthesis of conjugated enynes mentioned above and homoallylic halides as well as ring expansion and fission reactions . Herein, we report a one-pot, two-step TfOH-catalyzed hydroxylation/halocyclization of cyclopropyl methanols with H 2 O and NXS or Selectfluor (Scheme ).…”

“…As part of an ongoing program exploring the utility of alcohol pro-electrophiles in organic synthesis, − we recently described a regioselective route to conjugated enynes based on TfOH-catalyzed ring-opening of 1-cyclopropyl-2-propyn-1-ols with alcohols . On the basis of these earlier studies, we reasoned that a synthetic approach to 3-halohydrofurans could be achieved through NXS or Selectfluor-mediated cyclization of a homoallylic alcohol formed in situ from Brønsted acid-catalyzed hydroxylative ring-opening of cyclopropyl methanols.…”

Novel C-alkylation Reaction of Condensed Thiophenes with Enaminones, Enaminonitriles, Ethoxymethylene Malononitrile, Aryl Vinyl Ketones and ω-Nitrostyrenes

“…9 However, the 1 H NMR spectrum lacked the signals at d 5.0±6.0 ppm that would be expected for C-3 and C-5 of the thiepine moiety 8. 13,14 The 1 H NMR spectrum indicated the presence of two trans ole®nic protons at d H I 7.06 and 8.40 ppm with J 14 Hz. Thus, structures 9a±c were established for the reaction products.…”