82084-26-2Relevant academic research and scientific papers
Alkaline earth catalysis of alkynyl alcohol hydroalkoxylation/cyclization
Brinkmann, Christine,Barrett, Anthony G. M.,Reid, Stephanie,Hill, Michael S.,Procopiou, Panayiotis A.
, p. 7287 - 7297,11 (2020/09/02)
Heavier alkaline earth bis(trimethylsilyl)amides [Ae{N(SiMe 3)2}2]2 (Ae = Ca, Sr, Ba) are shown to act as effective precatalysts for the regioselective intramolecular hydroalkoxylation/cyclization of a wide range of alkynyl and allenyl alcohols. In the majority of cases, cyclization of alkynyl alcohols produces mixtures of the possible endo- and exocyclic enol ether products, rationalized as a consequence of alkynylalkoxide isomerization to the corresponding allene derivatives. Cyclization rates for terminal alkynyl alcohols were found to be significantly higher than for substrates bearing internal alkynyl substituents, while the efficacy of cyclization was in general found to be determined by a combination of stereoelectronic influences and the thermochemical viability of the specific alkaline earth metal catalysis, which we suggest is determined by the individual M-O bond strengths. Kinetic studies have provided a rate law pertaining to a pronounced catalyst inhibition with increasing [substrate], indicating that turnover-limiting insertion of C-C unsaturation into the M-O bond requires the dissociation of substrate molecules away from the Lewis acidic alkaline earth center.
Palladium-catalyzed, asymmetric Mizoroki-Heck reaction of benzylic electrophiles using phosphoramidites as chiral ligands
Yang, Zhigang,Zhou, Jianrong
supporting information; experimental part, p. 11833 - 11835 (2012/09/08)
We report herein the first examples of asymmetric Mizoroki-Heck reactions using benzyl electrophiles. A new phosphoramidite was identified to be an effective chiral ligand in the palladium-catalyzed reaction. The reaction is compatible with polar functional groups and can be readily scaled up. Several cyclic olefins worked well as olefin components. Thirty-one examples are included.
A Synthesis of 4-Oxo Carboxylic Acids, 4-Oxo Aldehydes, and 1,4-Diketones from γ-Lactones
Betancourt de Perez, Rosa M.,Fuentes, Lelia M.,Larson, Gerald L.,Barnes, Charles L.,Heeg, Mary Jane
, p. 2039 - 2043 (2007/10/02)
The α-methyldiphenylsilyl derivatives of γ-butyrolactone, γ-valerolactone, and the cis lactone of 2-hydroxycyclohexaneacetic acid have been reacted with Grignard reagents.The α-silylated lactones of γ-butyrolactone and γ-valerolactone react with a single equivalent of Grignard reagent to give a 2-substituted 4,5-dihydrofuran, which can be hydrolyzed and oxidized to 4-oxo carboxylic acids, 1,4-diketones, or 4-oxo aldehydes.The α-silylated fused lactone failed to react with ethylmagnesium bromide in refluxing tetrahydrofuran.An X-ray crystal structure of this silylated lactone indicated that this lack of reactivity is due to steric factors.
A FACILE SYNTHESIS OF 4-OXO CARBOXYLIC ACIDS FROM γ-BUTYROLACTONE
Fuentes, Lelia M.,Larson, Gerald L.
, p. 271 - 274 (2007/10/02)
An efficient, high-yield, three-step preparation of 4-oxo carboxylic acids from γ-butyrolactone via silylation and reaction with a Grignard reagent is presented.
