Regioselective Rh-Catalyzed Hydroformylation of 1,1,3-Trisubstituted Allenes Using BisDiazaPhos Ligand
作者:Josephine Eshon、Clark R. Landis、Jennifer M. Schomaker
DOI:10.1021/acs.joc.7b01140
日期:2017.9.15
The efficient hydroformylation of 1,1,3-trisubstituted allenes is accomplished with low loadings of a Rh catalyst supported by a BisDiazaPhos (BDP) ligand. The ligand identity is key to achieving high regioselectivity, while the mild reaction conditions minimize competing isomerization and hydrogenation to produce β,γ-unsaturated aldehydes and their derivatives in excellent yields.
Gold(I)-Catalyzed Rearrangement of Propargyl Benzyl Ethers: A Practical Method for the Generation and in Situ Transformation of Substituted Allenes
作者:Benoit Bolte、Yann Odabachian、Fabien Gagosz
DOI:10.1021/ja1020469
日期:2010.6.2
of benzyl propargyl ethers react with a gold(I) catalyst to furnish variously substituted allenes via a 1,5-hydride shift/fragmentation sequence. This transformation is rapid and practical. It can be performed under very mild conditions (room temperature or 60 degrees C) using terminal as well as substituted alkyne substrates bearing a primary, secondary, or tertiary benzyl ether group. The allenes
Synthesis and Functionalization of Allenes by Direct Pd‐Catalyzed Organolithium Cross‐Coupling
作者:Jaime Mateos‐Gil、Anirban Mondal、Marta Castiñeira Reis、Ben L. Feringa
DOI:10.1002/anie.201913132
日期:2020.5.11
A palladium-catalyzed cross-coupling between in situ generated allenyl/propargyl-lithium species and arylbromides to yield highly functionalized allenes is reported. The direct and selective formation of allenic products preventing the corresponding isomeric propargylic product is accomplished by the choice of SPhos or XPhos based Pd catalysts. The methodology avoids the prior transmetalation to other
Enabling the Rearrangement of Unactivated Allenes to 1,3-Dienes by Use of a Palladium (0)/Boric Acid System
作者:Marc Kimber、Yassir Al-Jawaheri、Matthew Turner
DOI:10.1055/s-0036-1591580
日期:2018.6
injection ESI-HRMS analysis we have detected and identified key π-allylpalladium complexes that support the addition of the palladiumhydridecomplex to the allene. A redox neutral rearrangement of an allene to a 1,3-diene by means of a unique palladiumhydridecomplex is reported. The palladiumhydridecomplex is generated from a simple Pd0 source and boric acid [B(OH)3], which is typically identified
Treatment of propargylic ethers with sodium dispersion in the presence of lithium iodide results in the generation of the corresponding carbanion species via cleavage of the propargylic C–O bond. The anionic species react with trimethoxyborane to yield the allenylboronates including highly substituted ones that are difficult to synthesize.