Propargylsilanes as Reagents for Synergistic Gold(I)‐Catalyzed Propargylation of Carbonyl Compounds: Isolation and Characterization of σ‐Gold(I) Allenyl Intermediates
Reported herein is the isolation and characterization, for the first time, of a σ‐gold allenyl complex as an intermediate in gold catalysis. This intermediate was captured during the study of a novel gold(I)‐catalyzed propargylation of carbonyl compounds with propargylsilanes. Notably, the gold‐catalyzed propargylation reaction, which proceeds with aldehydes and ketones, can be driven to the formation
The rates of monometallation of alkylphenylacetylenes
作者:James Y. Becker
DOI:10.1016/s0022-328x(00)84192-3
日期:1977.2
Alkylphenylacetylenes, C6H5CCCH2R, have been metallated at the propargylic positions with an excess of n-butyllithium in diethyl ether at 0°C. Mono- and di-silyl derivatives have been isolated by quenching the metallation mixtures with Me3SiCl at different times. Pseudo-first order rate constants have been calculated for the monometallation from the rate of formation of the silylated products. A Taft
Organomagnesium-Catalyzed Isomerization of Terminal Alkynes to Allenes and Internal Alkynes
作者:Raphaël Rochat、Koji Yamamoto、Michael J. Lopez、Haruki Nagae、Hayato Tsurugi、Kazushi Mashima
DOI:10.1002/chem.201500179
日期:2015.5.26
the transformation of these terminalalkynes into allenes and further to internalalkynes under mild conditions. To the best of our knowledge, this example is the first of an organomagnesium‐catalyzed isomerization of alkynes. Notably, the reactions proceeded through temporally separated autotandem catalysis, thus allowing the isolation of the allene or internalalkyne species in good yields. Mechanistic
intermediates, such as enynes and silylbenzofulvenes, have been isolated. Different control experiments have been performed, indicating the participation of [LAu][NTf2AlCl3] complex as the true catalyst, and revealing a dramatic enhancement of the gold activity by coordination of the Lewis acid to the gold counterion.