报道了用3-丁烯-1-醇对环丙烷甲醛的单步TiX 4介导的Prins型环化反应,以相对立体地构建相对应变的(E)-六氢氧代肟酸酯。将醇转换为3-butyn-1-ol引发了类似的路线,并在九元环内进行了另一个环化反应,从而得到了双环化产物(4,4-二卤代5-芳基氢环戊[ b ]吡喃)。容易将生成的二卤代双卤化物转化为乙烯基卤化物和酮,进一步补充了这种方法的实质。
报道了用3-丁烯-1-醇对环丙烷甲醛的单步TiX 4介导的Prins型环化反应,以相对立体地构建相对应变的(E)-六氢氧代肟酸酯。将醇转换为3-butyn-1-ol引发了类似的路线,并在九元环内进行了另一个环化反应,从而得到了双环化产物(4,4-二卤代5-芳基氢环戊[ b ]吡喃)。容易将生成的二卤代双卤化物转化为乙烯基卤化物和酮,进一步补充了这种方法的实质。
Substituent effects on the13C NMR spectra of ethylcis- andtrans-2-(p-substituted-phenyl)-1-cyclopanecarboxylates
作者:Yoshiaki Kusuyama、Kenjiro Tokami
DOI:10.1002/mrc.1260300415
日期:1992.4
13C NMR spectra were measured for a series of ethyl cis- and trans-2-(p-substituted - phenyl) - 1 - cyclopropanecarboxylates. The effects of the para substituents and the geometry on the chemical shifts are discussed.
Accessing Dihydro-1,2-oxazine via Cloke–Wilson-Type Annulation of Cyclopropyl Carbonyls: Application toward the Diastereoselective Synthesis of Pyrrolo[1,2-<i>b</i>][1,2]oxazine
作者:Pankaj Kumar、Rakesh Kumar、Prabal Banerjee
DOI:10.1021/acs.joc.0c00531
日期:2020.5.15
A convenient additive-free synthesis of dihydro-4H-1,2-oxazines via a Cloke-Wilson-type ring expansion of the aryl-substituted cyclopropane carbaldehydes with the hydroxylamine salt is introduced. Comparatively less active cyclopropyl ketones also follow a similar protocol if supplemented by catalytic p-toluene sulfonic acid monohydrate. The transformation is performed in an open-to-air flask as it
Metal-free domino Cloke-Wilson rearrangement-hydration-dimerization of cyclopropane carbaldehydes: A facile access to oxybis(2-aryltetrahydrofuran) derivatives
作者:Raghunath Dey、Shruti Rajput、Prabal Banerjee
DOI:10.1016/j.tet.2020.131080
日期:2020.4
demonstrated a metal-free transformation of cyclopropane carbaldehydes to oxybis(2-aryltetrahydrofuran) derivativesvia a domino Cloke-Wilson rearrangement-hydration-dimerization sequence. Commercially inexpensive p-toluene sulfonic acid (PTSA) was used as a Brønsted acid catalyst, and reactions were conducted in an open-flask. Detection of reaction intermediates were carried to get an insight into the