Palladium-Catalyzed α-Arylation of 2-Chloroacetates and 2-Chloroacetamides
摘要:
A method has been developed for the Pd-catalyzed synthesis of alpha-(hetero)aryl esters and amides through a Suzuki-Miyaura cross-coupling reaction. This method avoids the use of strong base, does not necessitate inert or low temperature formation of reagents, and does not require the use of a large excess of organometallic reagent. Utilization of organotrifluoroborate salts as nucleophilic partners allows a variety of functional groups and heterocyclic compounds to be tolerated.
Design and preparation of new palladium precatalysts for C–C and C–N cross-coupling reactions
作者:Nicholas C. Bruno、Matthew T. Tudge、Stephen L. Buchwald
DOI:10.1039/c2sc20903a
日期:——
of easily prepared, phosphine-ligated palladiumprecatalysts based on the 2-aminobiphenyl scaffold have been prepared. The role of the precatalyst-associated labile halide (or pseudohalide) in the formation and stability of the palladacycle has been examined. It was found that replacing the chloride in the previous version of the precatalyst with a mesylate leads to a new class of precatalysts with
compound in the presence of arylamine, furnishing the desired α -amino esters with moderate to high enantioselectivity and yield. More importantly, it was found there is a remarkable correlation between the enantioselectivity of product and substituent electronic parameter (σpara) of substrates. This work not only demonstrates chiral phosphoric acid catalysis is compatible with free carbene insertion reactions
一种促进以原子和可持续方式利用简单的高能中间体构建有价值的手性产物的方法,可以证明非常有助于不对称合成。游离卡宾是一种这样的高能中间体,由于存在严重的外消旋背景反应,它们在催化不对称反应中的应用仍然难以捉摸。在我们寻求开发游离卡宾的催化不对称 NH插入反应的过程中,在芳基胺存在下,在重氮化合物的可见光照射下,发现了原位生成的铵叶立德的一般手性 Brønsted 酸催化的对映选择性质子化,提供了所需的α-具有中等到高对映选择性和收率的氨基酯。更重要的是,发现产物的对映选择性与底物的取代基电子参数(σ para )之间存在显着的相关性。这项工作不仅证明手性磷酸催化与游离卡宾插入反应相容,而不会干扰失活 OH 插入副反应,而且还表明芳基胺的p Ka 也是改变反应对映选择性的重要参数。本文公开的方法有望为游离卡宾在无金属条件下催化不对称反应中的应用带来新的见解。
Leeuwen, Milko van; McKillop, Alexander, Journal of the Chemical Society. Perkin transactions I, 1993, p. 2433 - 2440
作者:Leeuwen, Milko van、McKillop, Alexander
DOI:——
日期:——
Identification of potent and novel small-Molecule inhibitors of caspase-3
作者:Darin A Allen、Phuongly Pham、Ingrid C Choong、Bruce Fahr、Matthew T Burdett、Willard Lew、Warren L DeLano、Eric M Gordon、Joni W Lam、Tom O'Brien、Dennis Lee
DOI:10.1016/j.bmcl.2003.08.024
日期:2003.11
The design and synthesis of a series of novel, reversible, small molecule inhibitors of caspase-3 are described. (C) 2003 Elsevier Ltd. All rights reserved.
Gas-phase replacement σ0 substituent constants of heteroaryl groups1
作者:Nouria A. Al-Awadi、Rasha F. Al-Bashir、Osman M.E. ElDusouqui