A transition-metal-free synthetic method of various ynones via decarboxylative alkynylation of α-keto acids is described. The reaction is carried out undermildconditions and exhibits remarkable tolerance of functional groups. The mechanism of a radical process is proposed in the reaction.
Rhodium-Catalyzed Isomerization of α-Arylpropargyl Alcohols to Indanones: Involvement of an Unexpected Reaction Cascade
作者:Ryo Shintani、Kazuhiro Okamoto、Tamio Hayashi
DOI:10.1021/ja042582g
日期:2005.3.9
alkynes + aromatic aldehydes), this method provides a new way of constructing indanones with high efficiency. By the mechanistic investigations using deuterium-labeled substrates, it has also been demonstrated that the reaction goes through an unexpected cascade, with a 1,4-hydrogen shift being the turnover-limiting step of the catalytic cycle.
Fast Oxy-Cope Rearrangements of Bis-alkynes: Competition with Central C−C Bond Fragmentation and Incorporation in Tunable Cascades Diverging from a Common Bis-allenic Intermediate
作者:Runa Pal、Ronald J. Clark、Mariappan Manoharan、Igor V. Alabugin
DOI:10.1021/jo101838a
日期:2010.12.17
oxy-Cope rearrangements of 1,5-hexadiyn-3,4-olates can be incorporated into cascade transformations which rapidly assemble densely functionalized cyclobutenes or cyclopentenones via a common bis-allenic intermediate. The competition between fragmentation, 4π-electrocyclic closure, and aldol condensation can be efficiently controlled by the nature of the acetylenic substituents. The rearrangement of bis-alkynes
As an update of our continuous interest in the hydrogenation of hydrazones, a chemo‐ and enantioselectivehydrogenation of alkynyl‐aryl hydrazones was developed using a rhodium complex [Rh((R,Sp)‐JosiPhos)(cod)]SbF6 as the catalyst and benzoic acid as an additive. Directed by a p‐nitrobenzamido group, the chiral propargyl hydrazines, which can be easily converted to chiral propargylamines of significant
作者:Shenghan Teng、Zhenguo Zhang、Bohan Li、Lanyang Li、Melinda Chor Li Tan、Zhenhua Jia、Teck‐Peng Loh
DOI:10.1002/anie.202311906
日期:2023.11.6
A novel type of silicon-containing alkynone reagents that target free thiols to produce the stable vinyl-sulfide linker under biocompatible conditions is reported. Besides simple aliphatic and aromatic thiols, this approach is also applicable to the labeling of thiols present in proteins, sugars and pharmaceuticals with full retention of silicon handles in most cases.