Under solvent-free conditions and at 80 °C, a DMAP- or imidazole-mediated clean and rapid conversion of cyclic Morita-Baylis-Hillman (MBH) acetates into the corresponding γ-keto allyl phosphonates in 70-93% yields is described herein. This allylic nucleophilic substitution works well with primary and secondary acetates bearing, at the β'-position, linear or branched alkyl groups and aryl groups.
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http://dx.doi.org/10.1021/acs.joc.5b02106 | DOI Listing |
JACS Au
January 2025
Laboratoire de Synthèse Organique (LSO-UMR 7652) CNRS, Ecole Polytechnique, ENSTA-Paris, Institut Polytechnique de Paris 828 Bd des Maréchaux, 91128 Palaiseau Cedex, France.
We report here the first example of a copper-catalyzed transformation involving nitro allyl derivatives. This borylation reaction, which exploits the high versatility of the aforementioned precursor, tolerates a variety of functional groups and allows practical, scalable, and highly straightforward access to diversely substituted allylboronic esters in high yields. The method was also extended to allyl sulfones, which provides a very complementary approach, offering additional structural diversity along with improved stereoselectivities.
View Article and Find Full Text PDFOrganometallics
January 2025
IU CINQUIMA/Química Inorgánica, Universidad de Valladolid, Valladolid 47071, Spain.
The reaction of diphosphino aryl complexes [Pd(CF)(L-L)(NCMe)](BF) (L-L = dppe, dppp, dppb) with diazoalkanes NCHR ( = -CH=CHPh, Ph) leads to η-allyl or η-benzyl palladium derivatives that are the organometallic products resulting from carbene-aryl coupling. The experimental trend shows that the reaction is favored for dppe > dppp > dppb. It involves several consecutive steps, i.
View Article and Find Full Text PDFJ Am Chem Soc
January 2025
Institut für Chemie, Technische Universität Berlin, 10623 Berlin, Germany.
A silylium-ion-promoted α-C-H allenylation of silyl ethers tethered to an internal alkyne is described. The actual intermolecular allenylation event occurs after the -selective hydrosilylation of the alkyne, where an in situ-generated β-silicon-stabilized vinyl cation engages in an intramolecular [1,5]-hydride shift. This process transforms the silyl ether into a silylcarboxonium ion, which reacts with propargylsilanes as nucleophiles, formed by the rapid silylium-ion-catalyzed isomerization of allenylsilanes.
View Article and Find Full Text PDFOrg Lett
January 2025
State Key Laboratory of Chemical Resource Engineering, Department of Organic Chemistry, College of Chemistry, Beijing University of Chemical Technology, Beijing 100029, People's Republic of China.
The reactivity of alkyl(aryl)phosphinic chlorides and imines was investigated in the presence of a base. The results indicated that allyl/benzyl(aryl)phosphinic chlorides gave rise to 1,2-azaphosphines (δ-phostims), while nonbenzylic alkyl(aryl)phosphinic chlorides produced the corresponding β-phosphinolactams (β-phostims) in their reaction with cyclic dibenzo[,][1,4]oxazepines, whereas steric electron-rich arylmethyl(aryl)phosphinic chlorides generated [2 + 2 + 2] annuloadducts in some cases. The current investigation provides useful insight into the reactivity of phosphinic chlorides and imines.
View Article and Find Full Text PDFJ Org Chem
January 2025
Department of Organic Chemistry, Stockholm University, SE-106 91 Stockholm, Sweden.
We have studied copper-catalyzed cross-coupling of chiral α-CF-substituted allylboronic acids with α-diazoketones. The reaction proceeds with excellent regioselectivity and stereoselectivity via allylic rearrangement. The method is useful for formation a new allylic C(sp)-C(sp) bond with high selectivity.
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