54522-92-8Relevant academic research and scientific papers
A highly active and air-stable ruthenium complex for the ambient temperature anti-markovnikov reductive hydration of terminal alkynes
Zeng, Mingshuo,Li, Le,Herzon, Seth B.
supporting information, p. 7058 - 7067 (2014/06/09)
The conversion of terminal alkynes to functionalized products by the direct addition of heteroatom-based nucleophiles is an important aim in catalysis. We report the design, synthesis, and mechanistic studies of the half-sandwich ruthenium complex 12, which is a highly active catalyst for the anti-Markovnikov reductive hydration of alkynes. The key design element of 12 involves a tridentate nitrogen-based ligand that contains a hemilabile 3-(dimethylamino) propyl substituent. Under neutral conditions, the dimethylamino substituent coordinates to the ruthenium center to generate an air-stable, 18-electron, κ3-complex. Mechanistic studies show that the dimethylamino substituent is partially dissociated from the ruthenium center (by protonation) in the reaction media, thereby generating a vacant coordination site for catalysis. These studies also show that this substituent increases hydrogenation activity by promoting activation of the reductant. At least three catalytic cycles, involving the decarboxylation of formic acid, hydration of the alkyne, and hydrogenation of the intermediate aldehyde, operate concurrently in reactions mediated by 12. A wide array of terminal alkynes are efficiently processed to linear alcohols using as little as 2 mol % of 12 at ambient temperature, and the complex 12 is stable for at least two weeks under air. The studies outlined herein establish 12 as the most active and practical catalyst for anti-Markovnikov reductive hydration discovered to date, define the structural parameters of 12 underlying its activity and stability, and delineate design strategies for synthesis of other multifunctional catalysts.
Rearrangement of indene skeletons under mild conditions
Kuninobu, Yoichiro,Ueda, Hirokazu,Kawata, Atsushi,Takai, Kazuhiko
, p. 6749 - 6752 (2008/02/11)
(Chemical Equation Presented) Isomerization between two isomers of 1,2-disubstituted 3-aminoindenes occurs via the rearrangement of indene frameworks. In contrast to previous rearrangements of indene derivatives, which occur under high-temperature conditi
Study of the mechanism of base induced dehydrobromination of trans-β-bromostyrene
Ma?kosza, Mieczys?aw,Chesnokov, Alexey A.
, p. 1995 - 2000 (2007/10/03)
Observation that rates of dehydrobromination of trans-β-bromostyrene (1) and the Hofmann degradation of tetrabutyl ammonium cation depend on strength of base in different ways and that treatment of 1 with base results in fast abstraction of the β-proton imply the possibility that the dehydrobromination of 1 could proceed via α-elimination and Ph migration. In order to clarify this question, β-13C-labeled 1 was obtained and subjected to PTC dehydrobromination which proceeds without migration of Ph. The obtained results are consistent with an irreversible E1cB mechanism.
Thermal Stereomutations of (2R,3R)-Phenylcyclopropane-1,2,3-2H3 and (1R,2S,3R)-Phenylcyclopropane-2-13C-1,2,3-2H3: Quantification of All Four Stereochemical Modes for Interconversions among the 1-Phenyl-1,2,3-trideuterocyclopropanes
Baldwin, John E.,Barden, Timothy C.
, p. 5312 - 5319 (2007/10/02)
Optically pure (2R,3R)-phenylcyclopropane-1,2,3-2H3 and (1R,2S,3R)-phenylcyclopropane-2-13C-1,2,3-2H3 have been prepared and the thermal stereomutations they exhibit have been followed kinetically at 309.3 deg C to provide the first complete quantificatio
