γ-Lactonizations of 2H-chromenes via cyclopropanation
摘要:
A two-step synthesis of tetrahydro-2H-furochromenones from 2H-chromenes is reported. The reaction of a series of tert-butyl 2-diazoacetate derivatives with 2H-chromenes, catalyzed by Rh(2)(OAc)(4), generated cyclopropane intermediates that rearranged to gamma-lactones on treatment with Sn(OTf)(2). (C) 2010 Elsevier Ltd. All rights reserved.
Rhodium-catalyzed cyclopropanations of 2-aryl-2H-chromenes with dialkyl malonate esters. A comparison of α-diazo derivatives and phenyliodonium ylides
作者:Sean Stokes、Rachel Mustain、Lydia Pickle、Keith T. Mead
DOI:10.1016/j.tetlet.2012.05.061
日期:2012.7
Rhodium-catalyzed reactions of 2-aryl-substituted 2H-chromenes with α-diazo esters prepared fromdimethyl and tert-butyl methyl malonates were investigated, and the results were compared with reactions carried out with phenyliodonium ylides prepared from the same esters. The phenyliodonium ylide prepared fromdimethylmalonate was found to give superior yields of cyclopropane products compared to the corresponding
Coupling of 2<i>H</i>-Chromenes with Silyl Ketene Acetals Enabled by Borane Catalysis
作者:Xin-Shen Liang、Rui-Dong Li、Wei Sun、Zhong Liu、Xiao-Chen Wang
DOI:10.1021/acscatal.2c02774
日期:2022.8.5
unknown in the literature. Herein, we report that this activity was observed with 2H-chromenes and the catalytic C(sp3)–H functionalization reaction based on this activity was established by using silylketeneacetals as the nucleophiles.
The various aspects presented herein relate to the cooling and flavor boosting compositions, and their use thereof.
Synthesis of pterocarpans through palladium-catalyzed oxyarylation of alkoxy-2H-chromenes with o-iodophenols
作者:Francisco V. Gaspar、Julio C.F. Barcellos、José F. Cívicos、Pedro Merino、Carmen Nájera、Paulo R.R. Costa
DOI:10.1016/j.tet.2020.131638
日期:2020.11
electron-donating (OMe) groups is studied under two experimental conditions: a) Pd(OAc)2, Ag2CO3 in PEG-400 at 140 °C, 10 min and b) oxime-based palladacycle, DIPEA, in PEG-400 at 150 °C, 3–4 h. Pterocarpans are obtained in moderate to good chemical yields.
γ-Lactonizations of 2H-chromenes via cyclopropanation
作者:Sean Stokes、Ben Spears、Cameron Laseter、Bobby Barker、Keith T. Mead
DOI:10.1016/j.tetlet.2010.05.059
日期:2010.8
A two-step synthesis of tetrahydro-2H-furochromenones from 2H-chromenes is reported. The reaction of a series of tert-butyl 2-diazoacetate derivatives with 2H-chromenes, catalyzed by Rh(2)(OAc)(4), generated cyclopropane intermediates that rearranged to gamma-lactones on treatment with Sn(OTf)(2). (C) 2010 Elsevier Ltd. All rights reserved.