A new coupling reaction of propargyl carbonates mediated by Ti(O i Pr) 2 Cl 2 /Mg
摘要:
A new homocoupling reaction of 1,1-disubstituted propargyl carbonates or 1-monosubstituted propargyl carbonates, mediated by Ti(OiPr)(2)Cl-2/Mg in ether at 0degreesC, was found to Corm symmetric 1,5-hexadiynes and 1-allenyl-5-ynes in moderate to high yields in various ratios. (C) 2002 Elsevier Science Ltd. All rights reserved.
Selective Alkenylation and Hydroalkenylation of Enol Phosphates through Direct CH Functionalization
作者:Xu‐Hong Hu、Xiao‐Fei Yang、Teck‐Peng Loh
DOI:10.1002/anie.201506437
日期:2015.12.14
Rh‐catalyzed direct CH functionalization reaction of enol phosphates was developed. The method is applicable to a variety of coupling partners, including activatedalkenes, alkynes, and allenes, and leads to the formation of various valuable alkenylated and hydroalkenylated enol phosphates through the action of the phosphate directing group. The versatility and utility of the coupling products were demonstrated
time. This protocol, merging visiblelight photoredox and palladium catalysis, provides a direct approach to conjugated tertiary allylic alcohol derivatives with broad functional group tolerance in moderate to excellent yields. Mechanistic studies suggest that, although two possible pathways exist in the transformation, radical oxyalkenylation promoted by visiblelight photoredox takes over the major
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.
Bifunctionalized Allenes. Part VIII. An Efficient and Varied Method for the Synthesis of 2-Sulfonylated Alka-2,3-Dienoates
作者:Ivaylo K. Ivanov、Valerij Ch. Christov
DOI:10.1080/10426507.2012.718299
日期:2013.7.1
Abstract An efficient and varied method for the synthesis of 2-sulfonylated alka-2,3-dienoates by intermediate formation of allenecarboxylates, allenyl sulfones, and propargyl sulfinates using the relatively high acidity of the hydrogen atom at the allenic C-1 atom and the [2,3]-sigmatropic rearrangement is described. Supplemental materials are available for this article. Go to the publisher's online
Palladium-Catalyzed Cocyclotrimerization of Allenes with Arynes: Selective Synthesis of Phenanthrenes
作者:Yi-Lin Liu、Yun Liang、Shao-Feng Pi、Xiao-Cheng Huang、Jin-Heng Li
DOI:10.1021/jo900117c
日期:2009.4.17
Palladium-catalyzed cocyclotrimerization of allenes with arynes has been developed for selectively synthesizing phenanthrenes. In the presence of [(allyl)PdCl]2 and P(o-tol)3, a variety of allenes, including internal and terminal allenes, underwent the cocyclotrimerization with arynes to afford the corresponding phenanthrenes in moderate to good yields. The results showed the selectivity of the reaction