A new domino reaction has been developed that allows the combination of styrenes and α‐alkyl ketone radicals to afford a wide array of polysubstituted furans in good to excellent yields under mild and simple reaction conditions. The key to success of this novel protocol is the use of photocatalyst fac‐Ir(ppy)3 and oxidant K2S2O8. Mechanistic studies by a radical scavenger and photoluminescence quenching
已开发出一种新的多米诺反应,该反应允许苯乙烯和α-烷基酮自由基的组合在温和简单的反应条件下以良好或优异的收率提供各种各样的多取代呋喃。该新协议成功的关键是使用光催化剂fac ‐Ir(ppy)3和氧化剂K 2 S 2 O 8。通过自由基清除剂和光致发光猝灭的机理研究表明,自由基加成/氧化途径是可行的。
A sequential synthesis of substituted furans from aryl alkynes and ketones involving a cerium(IV) ammonium nitrate (CAN)-mediated oxidative cyclization
作者:Sridhar Undeela、Joshi P. Ramchandra、Rajeev S. Menon
DOI:10.1016/j.tetlet.2014.08.039
日期:2014.10
A convenient, two-step synthesis of substitutedfurans from readily available aryl alkynes and ketones is reported. The furan-forming oxidative cyclization is mediated by the combination of cerium(IV) ammonium nitrate and potassium bromide and can be carried out in an open flask.
Efficient Generation and Increased Reactivity in Cationic Gold via Brønsted Acid or Lewis Acid Assisted Activation of an Imidogold Precatalyst
作者:Junbin Han、Naoto Shimizu、Zhichao Lu、Hideki Amii、Gerald B. Hammond、Bo Xu
DOI:10.1021/ol501443m
日期:2014.7.3
Brønsted or Lewis acid assisted activation of an imidogold precatalyst (L-Au-Pht, Pht = phthalimide) offers a superior way to generate cationic gold compared with the commonly used silver-based system. It is also broadly applicable for most common gold-catalyzed reactions. For reactions that require milder conditions, milder acids can be used for optimized efficiency.
A regioselectivesynthesis of multisubstituted furan derivatives has been developed via Cu(II)-catalyzed intermolecular annulation of aryl ketones with a wide range of aromatic olefins under ambient air in good yields. This protocol is applicable to both cyclic and acyclic aryl ketones.
Enhanced Reactivity in Homogeneous Gold Catalysis through Hydrogen Bonding
作者:Weibo Wang、Manish Kumar、Gerald B. Hammond、Bo Xu
DOI:10.1021/ol403584e
日期:2014.1.17
those instances where protodeauration is the rate-determining step. The efficiency of additives capable of hydrogen-bonding-assisted protodeauration correlated with their standing in a scale of hydrogenbonding basicity (measured by pKBHX). All additives used in the study are commercially available.
在原型脱氢是决定速率的步骤的情况下,良好的氢键受体添加剂可提高金催化反应的效率。能够进行氢键辅助原型脱氢的添加剂的效率与其在氢键碱度(以p K BHX衡量)中的地位相关。研究中使用的所有添加剂都是可商购的。