Synthesis of sterically hindered enamides via a Ti-mediated condensation of amides with aldehydes and ketones
作者:Julien Genovino、Bharat Lagu、Yaping Wang、B. Barry Touré
DOI:10.1039/c2cc32538a
日期:——
The first TiCl(4)-mediated condensation of secondary amides with aldehydes and ketones has been achieved. The reaction proceeds at room temperature and is complete within 5 h in most cases. The optimized procedure used 5 equiv of an amine base hinting that the in situ activation of both the amide and the Lewis acid is required. The reaction affords polysubstituted (E)-enamides.
作者:Vitaliy I. Timokhin、Natia R. Anastasi、Shannon S. Stahl
DOI:10.1021/ja0362149
日期:2003.10.1
Dioxygen-coupled oxidative amination of olefins is an attractive, but challenging, catalytic transformation. The present work describes the first general method for intermolecular oxidative amination of aryl olefins with molecular oxygen as the stoichiometric oxidant. This palladium-catalyzed reactivity is compatible with several different nitrogen nucleophiles, including oxazolidinone, phthalimide
Brønsted Base-Modulated Regioselectivity in the Aerobic Oxidative Amination of Styrene Catalyzed by Palladium
作者:Vitaliy I. Timokhin、Shannon S. Stahl
DOI:10.1021/ja0562806
日期:2005.12.1
Palladium(II)-catalyzed aerobic oxidative amination of styrene with oxazolidinone proceeds with catalyst-controlled regioselectivity: (CH3CN)(2)PdCl2 (1) and (Et3N)(2)PdCl2 (2) catalyze formation of the anti-Markovnikov and Markovnikov enecarbamate products, 3 and 4, respectively. Kinetic studies and deuterium kinetic isotope effects demonstrate that these two reactions possess different rate-limiting steps, and the data indicate that the product regiochemistry arises from the presence or absence of an effective Bronsted base in the reaction. In the presence of a Bronsted base such as triethylamine or acetate, the kinetically preferred Markovnikov aminopalladation adduct of styrene is trapped via rapid deprotonation of a zwitterionic intermediate and leads to formation of 4. In the absence of an effective Bronsted base, however, slow deprotonation of this adduct enables aminopalladation to be reversible, and product formation proceeds through the thermodynamically preferred anti-Markovnikov aminopalladation adduct to yield 3.