Additive‐Free Isomerization of Allylic Alcohols to Ketones with a Cobalt PNP Pincer Catalyst
作者:Brian Spiegelberg、Andrea Dell'Acqua、Tian Xia、Anke Spannenberg、Sergey Tin、Sandra Hinze、Johannes G. de Vries
DOI:10.1002/chem.201901148
日期:2019.6.12
Catalyticisomerization of allylic alcohols in ethanol as a green solvent was achieved by using air and moisture stable cobalt (II) complexes in the absence of any additives. Under mild conditions, the cobalt PNP pincer complex substituted with phenyl groups on the phosphorus atoms appeared to be the most active. High rates were obtained at 120 °C, even though the addition of one equivalent of base
Metal- and Acid-Free Methyl Triflate Catalyzed Meyer–Schuster Rearrangement
作者:Qingle Zeng、Lu Yang
DOI:10.1055/s-0036-1588800
日期:2017.7
acid-free preparation of synthetically useful α,β-unsaturated carbonyl compounds from propargyl alcohols has been realized. This Meyer–Schuster rearrangement process is effectively catalyzed by methyl triflate (20 mol%) to prepare a broad scope of conjugated E-enals and E-enones generally in good to excellent yields (up to 90%). This reaction procedure operates under mild conditions (70 °C), in air
A convenient general synthesis of 3-substituted 2H-chromene derivatives
作者:Perry T Kaye、Xolani W. Nocanda
DOI:10.1039/b201827f
日期:2002.5.10
Reactions of 2-hydroxybenzaldehydes and 2-hydroxy-1-naphthaldehydes with various activated alkenes under Baylis–Hillman conditions have been shown to proceed with regioselective cyclisation to afford the corresponding 3-substituted chromene derivatives. In some cases competitive dimerisation of the alkene component was observed, and direct dimerisation in the absence of the aldehyde has been explored.
Fe(OTf) 3 -catalyzed tandem Meyer-Schuster rearrangement/intermolecular hydroamination of 3-aryl propargyl alcohols for the synthesis of acyclic β-Aminoketones
作者:Ruiheng Tao、Yan Yin、Yongbin Duan、Yuxing Sun、Yue Sun、Fengkai Cheng、Jinpeng Pan、Cheng Lu、Yuan Wang
DOI:10.1016/j.tet.2017.02.030
日期:2017.3
Fe(OTf)3-catalyzed synthesis of acyclic β-aminoketones from 3-aryl propargyl alcohols and nitrogen nucleophiles were investigated. Results showed that propargyl alcohols without bulky groups α to the hydroxyl group underwent the transformation smoothly. Sulphonamides exhibited the higher reactivity than amides as the nitrogen nucleophiles and the transformation of acyclic β-aminoketones were finished
sulfur nucleophiles is reported. The investigation of the reaction substrates scope indicated that primary 3-aryl propargyl alcohols and thiols underwent the transformation smoothly. The reaction probably proceeded a Bi(OTf)3-catalyzed tandem Meyer-Schuster rearrangement of 3-aryl propargyl alcohol, followed by a thiol Michael conjugateaddition of thiols to in situ generated α, β-unsaturated ketones