Palladium-catalyzed, ligand-free S N 2’ substitution reactions of organoaluminum with propargyl acetates for the synthesis of multi-substituted allenes
作者:Xuebei Shao、Chang Wen、Gang Zhang、Kangping Cao、Ling Wu、Qinghan Li
DOI:10.1016/j.jorganchem.2018.06.020
日期:2018.9
We describe a convenient method for the synthesis of multi-substituted allenes from SN2′ substitution reactions organoaluminum with propargyl acetates: The SN2′ substitution reaction of organoaluminum (0.4 mmol) with propargyl acetates (0.5 mmol) mediated by PdCl2(dppf) (1 mol%) at 60 °C in THF without ligand could produce multi-substituted allenes in moderate to good yields (up to 98%) and high selectivities
An efficient and generalprotocol for the palladium-catalyzed Heck alkynylation of benzyl chlorides was developed. A catalyst system comprised of PdCl 2 (CH 3 CN) 2 and 2-dicyclohexyl-phosphino-2',4',6'-triisopropylbiphenyl (XPhos), with CS 2 CO 3 as the base, efficiently couples a wide range of functionalized terminalalkynes and substituted benzyl chlorides at 65 °C. We have also demonstrated that
The stereoselective synthesis of anti isomers of γ‐boryl‐substituted homoallylic alcohols is disclosed. (E)‐1,2‐Di(boryl)alk‐1‐enes undergo Ru‐catalyzed double‐bond transposition with control of the geometry. The in situ generated (E)‐1,2‐di(boryl)alk‐2‐enes add to aldehydes in a stereospecific manner. The alkenylboron group within the product is amenable to a variety of synthetic derivatizations.
of exploring new synthetic routes for obtaining this compound and analogues with improved bioactivity and lower toxicity. Herein, the chemical synthesis of carlina oxide analogues was developed. Their insecticidal activity was assessed on the vectors Musca domestica L. and Culex quinquefasciatus Say, and their cytotoxicity was evaluated on a human keratinocyte cell line (HaCaT). The compounds’ activity
1,3-Difunctionalization of Propargyl Silanes with Concomitant 1,2-Silyl Shift: Synthesis of Allyl Functionalized Vinyl Silanes
作者:Rūdolfs Beļaunieks、Mikus Puriņš、Rebeka Anna Līpiņa、Anatoly Mishnev、Māris Turks
DOI:10.1021/acs.orglett.3c01245
日期:2023.6.30
Terminal alkynes with a silylgroup at the propargylic position upon activation with electrophiles such as N-bromosuccinimide undergo (E)-selective 1,2-silyl group migration. Subsequently, an allyl cation is formed that is intercepted by an external nucleophile. This approach provides allyl ethers and esters with stereochemically defined vinyl halide and silane handles for further functionalization