Development of a general copper-catalyzed vinylic Finkelstein reaction—application to the synthesis of the C1–C9 fragment of laingolide B
作者:Antoine Nitelet、Kévin Jouvin、Gwilherm Evano
DOI:10.1016/j.tet.2016.07.018
日期:2016.10
conditions compatible with a range of highly functionalized substrates. The potential of this vinylic halogen exchange reaction in total synthesis and medicinal chemistry was demonstrated by its successful use for the synthesis of the C1–C9 fragment of laingolide B and for the late-stage modification of drug-like molecules. The extension of this halogen exchange to the acetylenic and allenic Finkelstein
Cobalt-catalyzed alkenylation of organomagnesium reagents
作者:Gérard Cahiez、Hovsep Avedissian
DOI:10.1016/s0040-4039(98)01266-0
日期:1998.8
Alkenyl iodides, bromides and chlorides react with organomagnesium reagents in THF, in the presence of Co(acac)2 and NMP (9 to 4 equiv.), to give the cross-coupling products in good yields. The reaction is chemoselective (aryl or alkyl bromides, esters and ketones) and stereoselective (≥99.5%).
Carbon-Carbon Bond Formation by Use of Chloroiodomethane as a C<sub>1</sub>Unit. I. Formation of Chloromethyltriphenylphosphonium Iodide, and Its Application for the Wittig Chloromethylenation of Aldehydes and Ketones
Chloromethyltriphenylphosphonium iodide has been prepared by the reaction of chloroiodomethane with triphenylphosphine. Upon treatment with potassium t-butoxide in t-butyl alcohol, the phosphonium iodide was converted into chloromethylenetriphenylphosphorane; this in turn was used for the Wittig reaction of aldehydes and ketones into the corresponding chloroolefins of the type RCH=CHCl and RR′C=CHCl in
mainly from the halo-λ3-iodane intermediate; the substitution occurs as a bimolecular reaction with the external halideion while the elimination is a unimolecular (intramolecular) reaction. The intermediacy of the hypervalent λ3-iodane as well as of the iodate are also confirmed by UV spectroscopy. The secondary kinetic isotope effects, leaving group substituenteffects, and pressure effects on the
Abstract A simple continuousflow synthesis of alkenyl chlorides from the corresponding readily available alkenyl iodides in copper reactor tubing is described. A variety of alkenyl chlorides were obtained in good to excellent yields with full retention of the double bond geometry. The reaction time was reduced by a factor of 24–48 compared to the batch process. A simple continuousflow synthesis of alkenyl