We have designed a new sequential carbocupration and sulfur-lithium exchange that leads stereo- and regioselectively to trisubstituted alkenyllithiums. Subsequent trapping with various electrophiles yields tetrasubstituted olefins with good control of the double-bond geometry (E/Z ratio up to 99:1). The novel sulfur-lithium exchange could be extended to the stereoselective preparation of Z-styryl lithium derivatives with almost complete retention of the double-bond geometry.
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http://dx.doi.org/10.3762/bjoc.8.248 | DOI Listing |
Org Lett
February 2021
Department of Chemistry, Drexel University, 32 South 32nd Street Philadelphia, Pennsylvania 19104, United States.
Oxazoles are rapidly assembled through a sequential deprotonation-condensation of Asmic, anisylsulfanylmethylisocyanide, with esters followed by sulfanyl-lithium exchange-trapping. Deprotonating Asmic affords a metalated isocyanide that efficiently traps esters to afford oxazoles bearing a versatile C-4 anisylsulfanyl substituent. Interchange of the anisylsulfanyl substituent is readily achieved through a first-in-class sulfur-lithium exchange-electrophilic trapping sequence whose versatility is illustrated in the three-step synthesis of the bioactive natural product streptochlorin.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
September 2020
Institute of Condensed Matter and Nanosciences, Molecular Chemistry, Materials and Catalysis, Université catholique de Louvain, 1348, Louvain-la-Neuve, Belgium.
Beilstein J Org Chem
February 2013
Department Chemie, Ludwig-Maximilians-Universität München, Butenandtstr. 5-13, 81377 München, Germany.
We have designed a new sequential carbocupration and sulfur-lithium exchange that leads stereo- and regioselectively to trisubstituted alkenyllithiums. Subsequent trapping with various electrophiles yields tetrasubstituted olefins with good control of the double-bond geometry (E/Z ratio up to 99:1). The novel sulfur-lithium exchange could be extended to the stereoselective preparation of Z-styryl lithium derivatives with almost complete retention of the double-bond geometry.
View Article and Find Full Text PDFChem Soc Rev
December 2008
Instituto de Síntesis Orgánica (ISO) and Departamento de Química Orgánica, Facultad de Ciencias, Universidad de Alicante, Apdo. 99, 03080 Alicante, Spain.
Multifunctional organic molecules can be accessed by reacting functionalised organolithium compounds (they can be prepared following a great number of different methodologies) with electrophilic reagents, this fact makes these intermediates of relevant interest in synthetic organic chemistry. Sulfur containing molecules have been used extensively as precursors of organolithium compounds by applying two different methodologies. One is the well-known alpha-deprotonation, which is not going to be the subject of this review, and the other methodology consists of sulfur lithium exchange by using lithium metal either alone or in the presence of a stoichiometric or catalytic amount of an arene.
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